i
Proceedings
Of
State Level Seminar on
Innovative Trends
in Physics
(ITP – 2016)
10th March 2016
Editors Mr. S. Arumugam, M.Sc., M.Phil.,
Mr. G. Lakshiminarayanan, M.Sc., M.Phil., Mr. S. Vasudevan, M.Sc., M.Phil., Mr. D. Gopinath, M.Sc., M.Phil.,
Organised by
PG & Research Department of Physics Shanmuga Industries Arts and Science College (Co-Ed)
(An ISO 9001-2008 certified institution), Certified Under Section 2(f) of the UGC Act 1956 Affiliated to Thiruvalluvar University, Vellore Manalurpet Road, Tiruvannamalai-606 603.
Phone : 04175-236654 / 237885 / 238744, Fax : 04175-237837 Email : [email protected], Web : www.shanmugacollege.org
Facebook : www.facebook.com / shanmugacollege
ii
All rights reserved. No part of this publication may be produced or transmitted in any form or by
any means, electronic or mechanical, including photocopying, recording,
or any information storage or retrieval system, without prior
permission in writing from the publishers.
No responsibility for loss caused to any individual or organization acting on or refraining from
action as result of the material in this publication can be accepted
By Darshan publishers or the author / editor
ISBN: 978–81–931973–8–7
Published by Darshan Publishers.
Rasipuram, Namakkal Dt., Tamilnadu.
This book is meant for educational and learning purposes. The author(s) of the book has/have taken all reasonable care to ensure that the contents of the book do not violate any existing copyright or other intellectual property rights of any person in any manner whatsoever. In the event the author(s) has/have been unable to track any source and if any copyright has been inadvertently infringed, please notify the Publisher in writing for corrective action.
iii
SHANMUGA INDUSTRIES ARTS AND SCIENCE COLLEGE (CO-ED)
TIRUVANNAMALAI
Lion S. Karthikeyan, B.com., MJF Secretary & Correspondent
Message I feel immense pleasure to note that Shanmuga
Industries Arts and Science College, an emerging
institution has initiated a remarkable attempt by
organizing a challenging State Level Seminar on
Innovative Trends in Physics (ITP-2016). It is my
privilege to highlight a few words of mine wishing the seminar and its proceedings.
Research is an action connected with the creation or innovation of fresh
processes, methods or services and using the newly discovered knowledge to
discharge a society or market need. Research must always be high value in order to
generate knowledge that is applicable outside of the research setting with
implications that go beyond the group that has participated in the research.
I believe that on the day stay here will create a spark in every participants’
mind to attain innovate some amazing stuffs in their carrier. Also I would like to
extend my wholehearted appreciation to all the organizers of this seminar for having
instigated and taken untiring endeavors to make this event an incredible one.
I wish the seminar to reap the rewards of great success.
Lion S. Karthikeyan, B.com., MJF
iv
Prof. AL. Udayappan, M.Sc., M.Phil., FICS.,
Academic Dean
Foreword It is a great pleasure to know that Shanmuga
Industries Arts and Science College, an emerging
institution has put forth a step forward by
organizing a challenging state level seminar on
Innovative Trends in Physics (ITP- 2016). I feel
honoured to pen a few words of mine wishing the
seminar.
Education is a medium of learning in which knowledge and skills of people
are reassigned from one generation to the next through teaching and research.
Further, scientific research is a generally used measure for judging the reputation of
an academic institution. I am very much happy that the staff and students of this
department of physics have realized the importance of this practice and they have
taken a unique initiative in organizing this state level seminar. I strongly believe that
this seminar is an arena to bring students’ and scholars’ inborn abilities and
endeavors to make realize their hidden skills. Also I hope that this seminar will
provide the correct platform for the researchers to get awareness on the latest trend in
the field of physics.
I wish each and every participant to make use of this opportunity to reach
their milestones and to make the event a memorable one. Also I express my heartfelt
appreciation to the organizers for having taken tireless efforts towards the success of
this event.
Prof. AL. Udayappan
v
Dr. K. Anandaraj, Ph.D.,
Principal
Foreword I am delighted to appreciate the organizing committee
members of the Department of Physics for bringing
out the proceeding of State Level Seminar entitled
Innovative Trends in Physics (ITP – 2016). This seminar is a benchmark and the result of
series of academic celebrations held in this regard. This
really encourages many innovative thickness to review
their positions in new research in scientific context. The outcome of this seminar has
been so enchanting that it would create enormous awareness and intellectual exercise
in this progressive field. Let this attempt be ennobling process of growth.
I once again congratulate the Head of the department of Physics for his
strenuous efforts to capture the essence of the state level seminar.
Good Luck
Dr. K. Anandaraj
vi
Mr. S. Arumugam, M.Sc., M.Phil.,
Convener & Head of Physics
Preface We, the organizing committee, extend our sincere
thanks to Shanmuga Industries Arts and Science
College for granting permission to organize the State
Level Seminar on Innovative Trends in Physics (ITP
– 2016) on 10th March 2016.
There are two invited talks by the experts and
38 contributed papers from various colleges. This
proceeding comprised of all the contributed papers. The special theme for this
seminar has been selected based on the current trends. More than 50 papers have
been reviewed and 38 papers have been accepted for oral presentation. The
following are the core areas under which the selected papers are categorized
Bio materials
Nanoscience and Nanotechnology
Crystallography
Acoustics
Semiconductor physics and Devices
Laser physics and Applications
Multifunctional Nanomaterials
Materials science
spectroscopy
We are highly grateful to the invited speakers, Dr. D. Sastikumar, Professor
of Physics, NIT, Trichy and Dr. R. T. Rajendrakumar, Associate Professor of
Physics, Bharathiar University, Coimbatore for having accepted our invitations to
make the event as a successful one. This State Level seminar is the outcome of
sincere and hardwork of so many hands and minds.
S. Arumugam
Convener & Head of Physics
ITP-2016
vii
ABOUT THE COLLEGE
Shanmuga Industries Arts and Science College, popularly known as SIASC,
is a Co-educational institution promoted by Shanmuga Industries Educational
Trust, Tiruvannamalai. The objective of the Trust is to enable the college into an
institution of excellence and to let the rural youth living in and around
Tiruvannamalai to have easy access to higher education. The college is situated in
Tiruvannamalai on the Tiruvannamalai-Manalurpet state highway. The premier
institute of college education was established in the year 1996. Since it’s founding,
SIASC has distinguished itself by providing a higher level of culture, cultivating
good discipline and finer value of life among students. SIASC, is one among the
leading institutions in the country to have been certified under section 2(f) of the
UGC Act 1956 and awarded with ISO 9001:2000 certificate and in recognition of
its quality standards. The facilities and infrastructure that the institution has, is
much above the benchmark propounded by the University.
ABOUT THE DEPARTMENT OF PHYSICS
The Department of Physics was established in the year 2004 with a view to
foster scientific temper among the students, to develop an independent thinking to
achieve their goal and to provide education at the Bachelor level in Basic science.
M.Sc., Physics and M.Phil., physics course was started in the year of 2012 and
2013 for the benefit of physics graduates. Since then 09 batches of B.Sc Physics,
02 batches of M.Sc., Physics and 02 batches of M.Phil., Physics students have
successfully completed their degree courses. The department has a team of well
qualified and experienced fourteen teaching faculties and two non teaching staff.
viii
ORGANIZING COMMITTEE
Secretary & Correspondent - Lion Mr. S. Karthikeyan, B.Com., MJF
Treasurer - Mr. S.D.R.S. Babu
Academic Dean - Prof. Al.Udayappan, M.Sc.,M.Phil.,FICS.,
Principal - Dr. K. Anandaraj
Convener - Mr. S. Arumugam, Head of Physics
Co-Convener - Mr. S. Vasudevan, Asst. Prof., Physics
INVITATION / REGISTRATION / RECEPTION COMMITTEE
Ms. V.K. Bhavanisathya - Coordinator, Asst. Prof., Physics
Ms. G. Nathiya - Asst. Prof., Physics
Mrs. Sudhalakshimi - Asst. Prof., Physics
PROGRAMME COMMITTEE
Mr. G. Lakshiminarayanan - Coordinator, Asst. Prof., Physics
Mr. K. Manivannan - Asst. Prof., Physics
PROCEEDING COMMITTEE
Mr. D. Gopinath - Coordinator, Asst. Prof., Physics
Mr. D. Arunkumar - Asst. Prof., Physics
CERTIFICATE COMMITTEE
Mr. D. Rajendiran - Coordinator, Asst. Prof., Physics
Mr. P.Mani - Asst. Prof., Physics
CATERING COMMITTEE
Mr. T. Ramamoorthy - Coordinator, Asst. Prof., Physics
Mr. P. Maniselvan - Asst. Prof., Physics
Mr. D. Siva - Asst. Prof., Physics
ix
Contents
S.NO. PAPER TITLE PAGE
NO.
1
2
3
4
5
6
7
8
9
THERMOACOUSTICAL STUDIES ON THE BINARY MIXTURES OF METHYL
AND ETHYL ACETATE IN 2-METHOXYETHANOL AT DIFFERENT
TEMPERATURES
G. Ravichandran and D.Gopinath
APPLICATION OF FT-IR SPECTROSCOPY TO STUDY THE
MINERALOGICAL COMPOSITION ON COASTAL SEDIMENTS FROM EAST
COAST OF TAMILNADU, INDIA
J.Chandramohan, M.Tholkappian, G.Elango and R.Ravisankar
ACOUSTICAL STUDIES ON THE EFFECT OF ELECTROLYTES ON THE
MICELLIZATION OF SODIUM CAPRYLATE AT 303.15 K
S.Arumugam and S.Maria Antony Pragash
ULTRASONIC STUDIES ON THE EFFECT OF ALCOHOLS ON THE MICELLATION
OF LITHIUM DODECYL SULPHATE IN AQUEOUS SOLUTION
G. Lakshiminarayanan and A.Anithadevi
GROWTH AND CHARACTERIZATION OF MORPHOLINIUM PERCHLORATE
A.Arunkumar , P. Ramasamy
GROWTH, STRUCTURAL, SPECTROSCOPIC, THERMAL AND HARDNESS
STUDIES OF CESIUM SULFAMATE SINGLE CRYSTAL
S.Rafi Ahamed and P.Srinivasan
INTRAMOLECULAR WEAK HYDROGEN BONDS IN SOME SIX AND FIVE
ATOM INTERACTIONS: SPECTROSCOPIC ANALYSIS
D.Nandha kumar and V.Periyanayagasami
GROWTH AND CHARACTERIZATION OF BIS THIOUREA POTASSIUM ACID
PHTHALATE (BTKAP) SINGLE CRYSTALS
N. Jhansi, K. Mohanraj and D. Balasubramanian
GROWTH, STRUCTURAL, THERMAL, AND MECHANICAL PROPERTIES OF
SUCCINIC ACID DOPED POTASSIUM HYDROGEN PHTHALATE (KHPSA)
CRYSTAL
R. Aruljothi, R. U. Mullai, E. Vinoth, M. Sheik Muthali, S. Vetrivel
1
11
23
31
39
43
56
65
72
x
10
11
12
13
14
15
16
17
18
19
GROWTH AND IN-VITRO STUDIES ON CYSTINE URINARY STONE IN
SILICA GEL MEDIUM
M.Saravana Kumar and F.Liakath Ali Khan
CHARACTERIZATION AND THEORETICAL PROPERTIES OF DIHYDROXY
COUMARIN, NLO SINGLE CRYSTAL BY DFT METHOD
K.Sambathkumar , R.saradha, A.Claude and K.Settu.
GROWTH AND CHARACTERIZATION OF POTASSIUM THIOCYANATE
DOPED POTASSIUM DI HYDROGEN ORTHO PHOSPHATE (KSCN-KDP)
CRYSTALS BY SR METHOD
B.Shalini
STRUCTURAL AND OPTICAL STUDIES OF WOLFRAMITE METAL
TUNGSTATES (M2+ WO4; M=CO & NI SYNTHESIZES VIA SONOCHEMICAL
PRECIPITATION TECHNIQUE
A.Sampathu, K. Ravichandran
EFFECT OF FE ON CERIUM OXIDE NANOPARTICLES
A.AArthi, P. Vijayashanthi, S. Shanmuga Sundari
GROWTH AND CHARACTERIZATIONS OF (TRI) GLYCINE BARIUM
CHLORIDE SINGLE CRYSTAL FOR OPTOELECTRONICS AND PHOTONICS
APPLICATIONS
S. Chennakrishnan, D. Sivavishnu, T. Kubendiran, S.M. Ravi Kumar
MEASUREMENT OF NATURAL RADIOACTIVITY AND ASSESSMENT OF
RADIOLOGICAL HAZARDS IN COASTAL SEDIMENTS OF CUDDALORE
COAST, TAMILNADU, INDIA
K. Thillaivelavan, N. Harikrishnan, G. Senthilkumar, R. Ravisankar
SYNTHESIS AND CHARACTERIZATION OF NANO ALUMINA BY TOP DOWN
APPROACH
S.Vasudevan and P. Kavithamani
ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL ON THE
MICELLATION OF SURFACTANT IN AQUEOUS SOLUTION AT FIXED
FREQUENCY 2 MHZ AND FIXED TEMPERATURE OF 303.15K.
G. Lakshiminarayanan and D. Arun kumar
NMR , NBO, AND VIBRATIONAL SPECTROSCOPIC ANALYSIS OF
O-NITROBENZAMIDE
D.Nandha kumar, P.Mani
82
87
102
110
120
127
136
146
154
159
xi
20
21
22
23
24
25
26
27
28
EFFECT OF ANNEALING PROCESS ON STRUCTURAL, MORPHOLOGICAL,
ELECTRICAL AND OPTICAL PROPERTIES OF CEO2 NANOPARTICLES
SYNTHESIZED BY CHEMICAL PRECIPITATION METHOD
K. Mohanraj, D. Balasubramanian, N. Jhansi, R. Suresh, C. Sudhakar
SYNTHESIS AND CHARACTERIZATION OF PURE AND L-ALANINE DOPED
AMMONIUM DIHYDROGEN PHOSPHATE(ADP)
R. Deepika, P. Meena
NOVEL SYNTHESIS ROUTE OF Γ- GLYCINE SINGLE CRYSTAL IN THE
PRESENCE OF 2-AMINOPYRIDINE POTASSIUM CHLORIDE FOR
OPTOELECTRONIC APPLICATIONS
R. Srineevasan
STRUCTURAL AND OPTICAL PROPERTIES OF ZINC OXIDE/MAGNESIUM
OXIDE (ZNO/MGO) NANOCOMPOSITES SYNTHESIZED BY THE FACILE
PRECIPITATION PROCESS
D. Siva , K. Anandan
ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL ON THE
MICELLATION OF SURFACTANT IN AQUEOUS SOLUTION AT FIXED
FREQUENCY 2 MHZ AND FIXED
TEMPERATURE OF 303.15K.
G. Lakshiminarayanan and D. Arun kumar
SYNTHESIS, GROWTH, STRUCTURE, OPTICAL, AND PHOTOCONDUCTING
PROPERTIES OF AN INORGANIC NEW NONLINEAR OPTICAL CRYSTAL:
SODIUM MANGANESE TETRA CHLORIDE (SMTC)
M. Packiyaraj, D.Sivavishnu, G.J. Shanmuga Sundar and S. M. Ravi Kumar
SYNTHESIS, STRUCTURAL, OPTICAL AND MORPHOLOGICAL PROPERTIES
OF (Co, Ag) doped ZINC OXIDE NANOPARTICLES
J.Balavijayalakshmi , K.Meena
ASSESSMENT OF HEAVY METAL POLLUTION IN COASTAL SEDIMENTS OF
EAST COAST OF TAMILNADU USING ENERGY DISPERSIVE X-RAY
FLUORESCENCE SPECTROSCOPY (EDXRF)
N. Harikrishnan, M. Suresh Gandhi, Durai Ganesh, A. Chandrasekaran, R. Ravishankar
SYNTHESIS, GROWTH AND PHYSICOCHEMIC AL PROPERITIES OF
DIAMMONIUM TETRACHLORO ZINCATE NLO CRYSTALS (DTCZ)
S.M.Ravikumar and G.Nathiya
169
180
186
202
211
216
225
231
248
xii
29
30
31
32
33
34
35
36
37
38
VARIATIONAL ITERATION METHOD FOR BURGER EQUATION
M.Sudhalakshmi, R.Sivakumar
GROWTH AND CHARACTERIZATION OF L-ALANINE MIXED BISTHIOUREA
CADMIUM BROMIDE(LABTCB) CRYSTAL
A. Maniselvan and T.Kubendiran
ULTRASONIC STUDIES ON THE EFFECT OF DMSO AND DMF ON THE
MICELLIZATION OF LITHIUM DODECYL SULPHATE
IN AQUEOUS SOLUTIONS
G. Lakshiminarayanan and R. Kumaresan
GROWTH AND CHARACTERIZATION OF BISTHIOUREA MANGANESE
SULPHATE SINGLE CRYSTAL BY SLOW EVAPORATION METHOD
H. Poornima
GROWTH AND PHYSICOCHEMICAL PROPERTIES OF A NEW
SEMIORGANIC NONLINEAR OPTICAL MATERIAL THIOUREA
POTASSIUM HYDROGEN PHTHALATE FOR NLO APPLICATIONS
A.Anbarasi, R.Srineevasan, M. Packiyaraj and S.M.Ravi Kumar
SOLUTION OF COUPLED NONLINEAR EQUATION BY
VARIATIONAL ITERATION METHOD
M.Sudhalakshmi, R.Sivakumar
ULTRASONIC STUDIES ON THE EFFECT OF DIOXANE AND
TETRAHYDROFURAN ON THE MICELLIZATION OF CETYL
TRIMETHYL AMMONIUM BROMIDE IN AQUEOUS SOLUTIONS
G. Lakshiminarayanan and D.Sakthivel
SYNTHESIS, GROWTH AND CHARACTERIZATION OF Cd2+ DOPED ZTS
CRYSTALS
J.Rajeswari
THERMAL AND ACOUSTICAL STUDIES ON SOME LIQUID ALKALI
METALS
P. Ramadoss, V. K. Bhavanisathya
HYDROTHERMAL SYNTHESIS OF CERIUM OXIDE NANO PARTICLES
P.Vijayashanthi, A.Aarthi, S. Shanmuga Sundari
257
268
276
282
288
296
311
317
323
330
1
THERMOACOUSTICAL STUDIES ON THE BINARY MIXTURES OF
METHYL AND ETHYL ACETATE IN 2-METHOXYETHANOL
AT DIFFERENT TEMPERATURES
G. Ravichandran* and D.Gopinath 1
* Post-Graduate and Research Department of Physics
Aringar Anna Government Arts College, Villupuram-605 602 1 Post-Graduate and Research Department of Physics
Shanmuga Industries Arts & Science College, Thiruvannamalai.
ABSTRACT
Density and ultrasonic velocity have been measured in the binary liquid
mixtures of methyl acetate (MA) and ethyl acetate (EA) in 2-methoxyethanol (2ME)
over the temperature range from 303.15 K to 323.15 K. The measured data are used
to compute the excess thermodynamic parameters namely excess adiabatic
compressibility (βsE), excess intermolecular free length (Lf
E) and excess molar
volume (VE). A plot of these excess thermodynamic parameters against the mole
fraction of methyl acetate and ethyl acetate over the entire composition range shows
a negative deviation indicating a strong interaction between the component
molecules of liquid mixtures. The results are discussed in terms of formation of
hydrogen bonding between the component molecules of the liquid mixtures.
Keywords: ultrasonic velocity, excess adiabatic compressibility, excess free length,
excess molar volume, hydrogen bonding.
1. Introduction:
The nature and the relative strength of the molecular interaction between the
component molecules of liquid mixtures have been successfully investigated by
many authors using ultrasonic method [1-9]. This is mainly due to the fact that the
ultrasonic velocity measured in pure liquids or liquid mixtures is fundamentally
related to the binding forces between atoms or molecules of a given liquid and
between the component molecules in the case of liquid mixtures. The excess
thermodynamic parameters calculated in liquid mixtures at various temperatures can
also provide information on the nature and degree of interaction between the
component molecules of the liquid mixtures. The deviation of excess thermodynamic
2
parameters with composition from its ideal behaviour gives a deep insight into the
various other dynamic processes that occur in the solutions [10-19].
In the present paper, we report on the results of nature of molecular interactions
between the molecules of the binary mixtures of methylacetate (MA) and
ethylacetate (EA) in 2-methoxyethanol (2ME) using excess thermodynamic
parameters like excess adiabatic compressibility (βsE), excess intermolecular free
length (LfE) and excess molar volume (VE) respectively in the temperature range
303.15 - 323.15 K.
2. Materials and method
The chemicals used in the present work are spectroscopic (SR) grade with a
minimum assay of 99.9 %. These chemicals were purchased from SD Fine
chemicals, India. The purity of the chemicals is checked by recording the IR
spectrum of each of these chemicals and comparing it with the standard spectrum
available in the literature. In all systems studied, the various compositions of the
binary liquid mixtures were prepared in terms of mole fraction.
The density and ultrasonic velocity were measured as a function of
composition of the binary mixtures at 303.15, 308.15, 313.15, 318.15 and 323.15 K
respectively.
The density of pure liquids and their liquid mixtures are measured using a
dilatometer of 20 ml capacity with the dilatometer immersed in a temperature
controlled water bath (accuracy ±0.01°). The accuracy in the measurement of
density of pure liquids and their liquid mixtures is ±2 parts in 104.
The ultrasonic velocity of the liquid mixtures has been measured using a
Digital Ultrasonic Velocity meter (Model VCT-70A, Vi-Microsystems Pvt. Ltd.,
Chennai, India) in the temperature range of 303.15 - 323.15 K by circulating water
from a thermostatically controlled water bath and the temperature being maintained
to an accuracy of ±0.01°.
Using the measured values of ultrasonic velocity and density, various excess
thermodynamic parameters such as excess adiabatic compressibility (βsE), excess
free length (LfE) and excess molar volume (VE) have been calculated using the
equations,
3
calsE
s 12 (1)
where
2211 sXsXcals
calff
Ef LLL 12 (2)
where
2211 ffcalf LXLXL
(3)
where
12
2211
MXMXVobs
2
22
1
11
MXMXVcal
where M1, M2, X1, X2, ρ1, ρ2, ρ12, βs1, βs2, βs12 , Lf1, Lf2 , Lf12 are the molecular
weight, mole fraction, density, adiabatic compressibility and intermolecular free
length of the components 1 and 2 and their mixtures respectively.
All the excess thermodynamic parameters were fitted to Redlich-Kister
equation
N
j
jj
E XAXXY1
11121 )12( (4)
and the parameters Aj-1 were computed using least square fit method.
3. Results and Discussion:
The ultrasonic velocity measurements are carried out in the binary mixtures of
methyl acetate-2methoxyethanol (MA-2ME) and ethyl acetate-2methoxyethanol
(EA-2ME) at different temperatures. The experiment was carried out in the
composition range of X1=0 to 1 mole fraction of methyl and ethyl acetates. The
measured density and the density values reported in the literature for methyl acetate,
ethyl acetate and
2-Methoxyethanol are given in Table1.
Using the measured values of ultrasonic velocity and density for the binary
mixtures of MA-2ME and EA-2ME are calculated and are presented in Tables 2 & 3.
calobsE VVV
4
The coefficients of equation (4) viz., A0 to A3 computed for βsE, LfE and VE by least
square fitting method along with the standard deviations (σ) are given in Tables 4 &
5. The variation of excess thermodynamic parameters such as excess adiabatic
compressibility (βsE), excess freelength (LfE) and excess molar volume(VE) with
increasing concentration of methyl and ethyl acetates (X1 = 0 to 1 mole fraction) are
shown in figures 1-6.
3.1 Methyl acetate – 2 Methoxyethanol system (MA-2ME):
Figure 1 shows that the excess adiabatic compressibility at 303.15 K has a
negative deviation for the entire concentration range of methyl acetate. The
magnitude of negative deviation reaches a maximum at X1=0.4983 mole fraction of
MA and then becoming less and less negative with further increase in concentration
of MA in 2ME. The excess free length and excess molar volume also exhibits a
similar behaviour as that of excess adiabatic compressibility at 303.15 K. The
observed negative deviation of βsE, LfE and VE at 303.15 K from the ideal behaviour
can be explained as follows;
Generally, liquid mixtures which show non-linearity in ultrasonic velocity
with concentration can be analysed in terms of excess thermodynamic functions.
This is due to the fact that the excess thermodynamic functions are found to be
sensitive towards the mutual interactions between the component molecules of the
liquid mixture. In ideal mixtures, the physical property of the mixture may be
evaluated as a sum of fractional contribution from the individual components. But,
non-ideal mixtures show considerable deviation from linearity in their physical
property with respect to concentration and these have been interpreted as arising due
to strong or weak interactions. The sign and the extent of deviation of these
functions from ideality depend on the nature of constituents and composition of the
mixtures [20,21].
The negative deviation exhibited by excess adiabatic compressibility at
303.15 K becomes increasingly negative reaching a maximum at X1= 0.4983 mole
fraction of MA. This may be due to increasing strength of interaction between the
components of liquid mixture. The greater negative deviation of βsE for MA-2ME
system suggests that a specific molecular interaction is likely to operate between
2ME and MA molecules leading to the formation of a complex. In MA-2ME
5
system, 2ME is a highly associated liquid and MA is highly polar and also a proton
acceptor. Hence, in the present binary mixture MA-2ME, in general the interaction
responsible for association may be likely due to hydrogen bonding, dipole-dipole
interactions or formation of complexes due to charge transfer. In MA-2ME system,
the complex formation may be through hydrogen bonding between 2ME and MA
molecules. From the structure of the molecules of the constituents, it can be inferred
that the oxygen atom of carbonyl group (C=O) of MA may be involved in O-H---O
bonding with the hydroxyl group (OH) of 2ME molecule with the strength of
bonding becoming maximum at X1= 0.4983 mole fraction of MA . The present
study is supported by the ultrasonic studies carried in the binary mixtures of
dimethylsulphoxide - acetone carried out by Syal et al [22], and in some monohydric
alcohols in dimethylsulphoxide carried out by Palani et al [23].
LfE at 303.15 K also shows negative deviation for the entire composition
range of MA showing maximum negative deviation at X1 =0.4983 mole fraction of
MA (Figure.2). The negative deviation in LfE indicates that ultrasonic waves cover a
longer distance due to decrease in intermolecular free length describing the dominant
nature of hydrogen bonding between unlike molecules of the binary mixture. A
similar type of studies was reported by Rajagopal and Chenthilnath [15] in the binary
mixtures of 2- methyl-2 propanol in acetophenone.
The excess molar volume (VE) for MA-2ME system in the temperature range
studied also shows a negative deviation for the entire composition range of MA with
the maximum negative deviation occurring at X1= 0.4983 mole fraction (Figure 3).
The changes in VE is influenced by two factors namely,
(i) loss of dipolar association and differences in size and shape and
(ii) dipole-dipole, dipole-induced dipole interaction, charge transfer
complexation and hydrogen bonding between unlike molecules.
The former effect leads to expansion in volume and the latter contributes a
contraction in volume. The actual value of VE depends on the balance between these
two opposing contributions [24]. Large negative values of VE indicate strong
interaction between unlike molecules [11]. Such a large negative deviation in VE is
observed in the present MA-2ME system. The greater negative deviation is due to
the formation of hydrogen bonding between 2ME and MA molecules.
6
As the temperature is increased to 308.15, 313.15, 318.15 and 323.15 K, the
maximum negative deviation of βsE, LfE and VE further increases and is more
pronounced at 323.15 K compared to their values in other temperatures respectively.
This indicates that the complex formation is more favoured at 323.15 K rather than
at other temperatures. This can be explained as follows:
At 303.15 K, 2ME is self associated through hydrogen bonding. At higher
temperatures due to thermal agitation, self associated 2ME molecules are disrupted,
and this facilitates the interaction between 2ME and MA molecules through the
formation of intermolecular hydrogen bonding. Thus, at a higher temperature of
323.15 K, probably the interaction is stronger than that at other temperatures. This
observation is further supported by the conclusions drawn by Chauhan et al. [25], in
their ultrasonic velocity studies carried out in the binary mixtures of acetonitrile-
propylene carbonate in the temperature range 298 K – 318 K. The interaction
between acetonitrile and propylene carbonate molecules becoming stronger at 318 K
than at 298 K.
3.2 Ethyl acetate – 2Methoxyethanol system(EA-2ME):
In EA-2ME system, the variation of excess thermodynamic functions βsE, LfE
and VE at all temperatures studied are shown in Figures 4-6. All these excess
parameters show a negative deviation for the entire composition range of EA (X1=0-
1 mole fraction) and for the temperature range studied. The negative deviation of
βsE, LfE and VE increases with increase of temperature showing maximum deviation
at 323.15 K. The magnitude of negative deviation reaches a maximum at X1=0.5463
mole fraction of EA and then becoming less and less negative with further increase
in concentration of EA in 2ME.
The negative deviation of βsE, LfE and VE observed in EA-2ME system at all
the temperatures studied is similar to that in MA-2ME system, so the explanation
offered for MA-2ME system is equally applicable to EA-2ME system. The negative
deviation of βsE , LfE and VE increases with increase of temperature reaching a
maximum at 323.15K. This indicates that the complex formation is much stronger at
323.15 K.
7
0.0 0.2 0.4 0.6 0.8 1.0-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1Figure 1
MA + 2ME at 303.15 K MA + 2ME at 308.15 K MA + 2ME at 313.15 K MA + 2ME at 318.15 K MA + 2ME at 323.15 K
Molefraction of methylacetate (X1)
(sE )
X10
-11 m
2 N-1
0.0 0.2 0.4 0.6 0.8 1.0-2.6
-2.4
-2.2
-2.0
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2Figure 2
MA + 2ME at 303.15 K MA + 2ME at 308.15 K MA + 2ME at 313.15 K MA + 2ME at 318.15 K MA + 2ME at 323.15 K
Molefraction of methylacetate (X1)
( L fE )
x 1
0-12 m
8
0.0 0.2 0.4 0.6 0.8 1.0-1.3
-1.2
-1.1
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1Figure 3
MA + 2ME at 303.15 K MA + 2ME at 308.15 K MA + 2ME at 313.15 K MA + 2ME at 318.15 K MA + 2ME at 323.15 K
Molefraction of methylacetate (X1)
(VE )
x10-7
m3 m
ol-1
0.0 0.2 0.4 0.6 0.8 1.0-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5Figure 4
EA + 2ME at 303.15 K EA + 2ME at 308.15 K EA + 2ME at 313.15 K EA + 2ME at 318.15 K EA + 2ME at 323.15 K
Molefraction of ethylacetate (X1)
(sE )
X10
-11 m
2 N-1
9
0.0 0.2 0.4 0.6 0.8 1.0
-1.0
-0.8
-0.6
-0.4
-0.2
0.0Figure 5
EA + 2ME at 303.15 K EA + 2ME at 308.15 K EA + 2ME at 313.15 K EA + 2ME at 318.15 K EA + 2ME at 323.15 K
Molefraction of ethylacetate (X1)
( L fE )
x 1
0-12 m
0.0 0.2 0.4 0.6 0.8 1.0
-6
-5
-4
-3
-2
-1
0 Figure 6
EA + 2ME at 303.15 K EA + 2ME at 308.15 K EA + 2ME at 313.15 K EA + 2ME at 318.15 K EA + 2ME at 323.15 K
Molefraction of ethylacetate (X1)
(VE )
x10-7
m3 m
ol-1
10
4. Conclusion: The excess thermodynamic functions such as βsE, Lf
E and VE are calculated for the binary mixtures of methyl acetate-2methoxyethanol and ethyl acetate-2 methoxyethanol in the temperature range 303.15 K – 323.15 K. All these parameters show negative deviation in the composition range X1= 0-1 mole fraction of methyl acetate and ethyl acetate in 2-methoxyethanol and at all the temperatures studied. Both the binary mixtures show a maximum negative deviation at 323.15 K indicating that the complex formation is much stronger at this temperature. In the binary mixtures studied, the formation of complexes is due to the formation of hydrogen bonding between the oxygen of carbonyl group (C=O) of methyl acetate, ethyl acetate with the hydroxyl group (OH) of 2-methoxyethanol. References :
[1] A Kumar, Colloids and Surfaces, 34 313 (1989) . [2] J D Pandey, G P Dubey, B P Shukla, S N Dubey, Pramana J. Phys. 37 443(1991) [3] S L Oswal, R P Phalak, J. Sol. Chem. 22 43 (1993) . [4] T M Aminabhavi and K Banerjee K. J. Chem. Eng. Data, 43 (1998) 514. [5] Krzyszt of Bebek, Mole. Quant. Acous., 26 15 (2005) [6] Anil Kumar Nain, Bull. Chem.Soc. Jpn, 79 1688 (2006) [7] S Ravichandran and K Ramanathan , Poly. Plast. Tech Engg, 47 169 (2008). [8] G Arul and L Palaniappan , Ind. J Pure. Apple Phys. 43 755 (2005). [9] G Parthiban, G Arivazhagan, M Subramanian and T Thenappan, Physics and Chem.,of Liqs, 49(1) ( 2011). [10] G Ravichandran and K Govindan , Indian J Pure & Appl Phys, 32 852 (1994) [11] G Ravichandran and K Govindan , J Sol Chem., 25 75 (1996) . [12] Eduardo J M Filipe, Luis F G Martins , Jorge C.G.Calado Clare Mccabe and George Jackson, J.Phys.Chem., B, 104 1322 (2000). [13] A toumi, N Hafaiedh and M Bouanz, Fluid Phase equilibria, 278 68 (2009). [14] G Nath & R Palikary , Indian J Phys, 83 (9) 1309 (2009) . [15] K Rajagopal and S Chenthilnath , Indian J Pure & Appl Phys, 48 326 (2010) . [16] Gyan Prakash and Dubey Krishnakumar,Thermochimica Acta, 524 7 ( 2011). [17] Harishkumar, Rajendrakumar and Dheeraj, K. J. Pure. Appl.&Indus. Phys, 1(4) 260 (2011). [18] S Elangovan and S Mullainathan Indian J. Phys. 86 727 (2012) [19] G Arivazhagan, M Mahalakshmi and SAJ Zahira Indian J. Phys. 86 493 (2012) [20] R J Fort and H Moore , Trans Faraday Soc, 61 2102 (1965) . [21] R J Fort and H Moore , Trans Faraday Soc, 62 1112 (1966) . [22] Syal V K Chauhan and S Uma Kumari, Indian J Pure & Appl Phys, 43 844 (2005) [23] R Palani , S Saravanan and R Kumar , Rasayan J Chem, 2 (3) 622 (2009) . [24] A Krishnaiah , D N Rao and P R Naidu , Polish J Chem, 55 2633 (1981) . [25] M S Chauhan , K C Sharma , S Gupta , M Sharma & S Chauhan , Acoustic Letters, 18 233(1995) . [26] “Spectroscopic Identification of Organic Compounds” by Robert Silverstein M, Clayton Bassler G & Terence Morrill C, John Wiley & Sons, New York (1981).
11
Application of FT-IR Spectroscopy to study the Mineralogical Composition on
Coastal Sediments from East Coast of Tamilnadu, India
J.Chandramohan1, M.Tholkappian2, G.Elango3 and R.Ravisankar4
1Department of Physics, E.G.S. Pillay Engineering College, Nagapattinam –
611002, Tamilnadu, India 2Department of Physics, Sri Vari College of Education, Tiruvannamalai, 606611,
Tamilnadu, India 3Post Graduate and Research Department of Chemistry, Government Arts College,
Tiruvannamalai-606603, Tamil Nadu, India 4Post Graduate and Research Department of Physics, Government Arts College,
Tiruvannamalai-606603, Tamil Nadu, India
E-Mail: [email protected]
ABSTRACT
FT-IR spectroscopy has recently received attention for its potential use in
quantitative mineral analysis. The Fourier Transform Infrared (FT-IR) absorption
spectra of sediments contain more information about mineralogy. In the present
study, coastal sediments collected from Pattipulam to kaipanikuppam along the East
Coast of Tamilnadu is subjected to mineral analysis using FT-IR technique. From the
infra spectrum, the minerals are identified from the location or band position of
peaks with the help of available literature. The infrared analyses of sediment samples
indicate the presence of quartz, microcline, orthoclase, albite, kaolinite,
montmorlinite, calcite, aragonite and organic carbon. Among the different minerals
quartz is present invariably in all the samples. The accessory minerals are identified
as kaolinite, montmorlinite, calcite and aragonite from the i.r. study. FT-IR
technique gives the useful information about the mineralogical composition of the
sediments.
Keywords: Sediment, Mineral Analysis, FT-IR spectroscopy
1.0. INTRODUCTION
Sediments are complex mixtures of inorganic and organic components.
Analysis of sediments provides environmentally significant information. Sediment
12
plays a predominant role in aquatic radioecology and plays a role in accumulating
and transporting contaminants within the geographic area. Sediment composition is
determined by their source and biotic transformations with respect to time [1].
Coastal sediments usually act as sinks of river borne metals released through
weathering and human activities in terrestrial environments [2-4].
The mineral analysis in sediment is one of the key researches for geologist to
identify the heavy minerals in coastal areas. There are number of techniques
available for the mineral identification over a decade. Among the number of
techniques FT-IR is a potential tool for mineral analysis due to its non-destructive
and rapid analysis. FT-IR spectroscopy can provide detailed information on organic
and inorganic constituents of sediment records. FT-IR is used to identify various
chemical groups including functional group present in the mineral constituents of the
sediments and also alternative method for acquiring quantitative mineralogy. FT-IR
spectroscopy has certain advantages such as requirement of small quantity of sample,
fast and easy method of sample preparation and short time to analysis.
In the present study, a mineralogical investigation on coastal sediment
samples from Pattipulam to kaipanikuppam of East coast of Tamilnadu has been
carried out using FT-IR technique. The study area presents a great interest because of
the manufacturing unit, mini industries, chemical industries etc.
2.0 MATERIALS AND METHODS
2.1 Sample Collection
Sediment samples were collected along the Bay of Bengal coastline, from
Pattipulam to kaipanikuppam coast during pre-monsoon condition. Sampling
locations were selected to collect representative samples from all along the study
area. Table 1 represents the geographical latitude and longitude for the sampling
locations at the study area. In order to ensure minimum disturbance of the upper
layer, samples were collected by a Peterson grab sampler from 10 m water depths
parallel to the shoreline. The grab sampler collects 10 cm thick bottom sediment
layer from the seabed along the 11 stations. Each sample of about 2 kg was kept in a
thick plastic bag and transported to the laboratory. The collected from different sites
under study were labeled as PPM, DVN, MAM, KKM, KPM, VPC, TPM, MKM,
13
OKM, APT and KPK. The distance between each station falls around 10kms. The
location map is given in Fig. 1.
Table -1 Latitude and longitude of Locations
S. No Sample ID Latitude(N) Longitude(E) Location
1 PPM 12°40'51.27"N 80°15'19.35"E Pattipulam
2 DVN 12°39'19.32"N 80°14'49.68"E Devaneri 3 MAM 12°37'55.53"N 80°14'13.14"E Mahabalipuram 4 KKM 12°34'56.33"N 80°13'22.37"E Kokilamedu 5 KPM 12°30'57.52"N 80°11'50.57"E Kalpakkam 6 VPC 12°27'58.97"N 80°11'16.29"E Veppancheri 7 TPM 12°24'42.28"N 80° 9'48.29"E Thenpattinam 8 MKM 12°21'26.51"N 80° 6'52.67"E Mudaliyarkuppam 9 OKM 12°19'35.89"N 80° 5'44.70"E Odiyurkuppam
10 APT 12°16'19.80"N 80° 3'16.00"E Alampara fort
11 KPK 12°12'42.65"N 80° 1'32.40"E Kaipanikuppam
Fig 1-Location Map of the Study area
14
2.2 Sample Preparation and Analysis
The KBr pellet technique was followed by mineral analysis. A sample of 2
mg is mixed with 40 mg of spectroscopic KBr in the ratio 1:20 using a mortar and
pestle. Before mixing, the necessary amount of KBr powder is dried at 120°C for 6
hours in an oven. Otherwise the broad spectral peak due to free OH will seriously
affect the interpretation of the bound hydroxyls associated, with any of the mineral.
The major and minor minerals are qualitatively determined by FT-IR technique. For
each samples the spectra were taken in the mid region of 4000-400cm-1. Such
coverage range ensures that most of the useful vibrations active in the IR will be
included. The instrument scans the spectra 16 times in 1 minute and the resolution is
5cm .This instrument is calibrated for its accuracy with the spectrum of a standard
polystyrene film. Every time, before the spectrum of sample is obtained; the
spectrum of the polystyrene film is taken and checked for the accuracy and
transmittance. The best spectrum for each site was considered as a representative
spectrum of the site. The typical FT-IR spectrum is shown in Fig. 2.
Fig. 2. A Representative FT-IR spectrum of coastal sediment sample
15
Table 2 FT-IR observed absorption bands (cm-1) of coastal sediment
samples of East Coast of Tamilnadu with mineral identifications
Silicate
Mineral Feldspar Clay Minerals
CARBONATE
MINERALS Sample
ID Quartz
Micro
cline
Ortho
clase Albite
Kaoli
nte
Montm
orlinite
Orga
nic
Carbo
n Calci
te
Argaon
ite
PPM
459, 695,
778, 795,
1616,
1875
425,
460,
535,
642
432,
467,
536, 580
485,
420,
575,
785,
990
935,
1030,
3420
876,
1640
2854,
2926
715,
1414
,
1795
855,
1475
DVN
455, 695,
780,
1080,
1875
427,
462,
645,
742
537, 584 787,
990
471,
3425
480,
1640
2850,
2930
715,
1420
1460,
1790
MAM
455, 695,
775,
1616,
1875
464,
586,
640
469, 536 405,
420
3425,
1030
3140,
1640
2851,
2925
715,
878,
2515
856,178
8
KKM
455, 695,
775,
1082,
1875
428,
464,
534,
643,
742
469, 583
579,
787,
995
939,
3425,
1030
480,
875
2854,
2929
875,
1795
1476,
1790
KPM 458, 697,
779, 1873
428,
461,
534,
640
467,
1040,
581, 648
405,
422,
990,
1095
475,
1030,
1115,
3420
1643,
3441
2851,
2925
1412
,
1795
1785
VPC
460, 775,
795,
1080,
1875
463,
587,
640,
1051
584, 650
525,
785,
990,
1095
1030,
920,
475
1645,
3440 2857
715,
1416 855
16
TPM
458, 695,
776,
1082,
1616,
1873
462,
642
435,
467,
540, 581
420,
785,
993
920,
3425
480,
826
2855,
2930
715,
875,
2515
1460,17
89
MKM
695, 775,
1085,
1615,
1875
428,
462,
590,
640
538,
1040
575,
785,
1095
940,
1030,
3425
478,
878
2852,
2925
715,
1417
,
1798
855,
1785
OKM
457, 780,
795,
1085,
1620
426,
644,
1060
536,
648,
1011,
1040
405,
420,
575
939,
3425
1640,
3433 2929
875,
1418
1480,
1790
APT
455, 698,
1085,
1620,
1875
430,
534,
643
469,
538, 584
790,
425,
995
427,
1030,
1115
1643,
1445
2855,
2926
715,
1795
855,178
5
KPK
455, 655,
7751,
108, 1875
463,
587,
640
434,
466,
536, 582
405,
420,
575
1030,
3425
480,
825
2854,
2926
715,
1420
,
2515
855,
1460,
1790
3.0. RESULTS AND DISCUSSION
The absorption frequencies of the peaks in the spectra of each site in wave
number unit (cm-1) are reported in Table 2. By comparing the observed frequencies
with available literature [5-11], the minerals such as quartz, microcline, orthoclase,
albite, Kaolinite, montmorlinite, calcite and aragonite have been identified. The
mineral wise discussion is outlined is given below.
3.1. Quartz
Quartz is a silicate mineral. It forms most abundant mineral in the Earth’s
crust. It is present in many sediments as well as sedimentary and igneous rocks. The
IR absorption peaks of quartz were reported by many workers [12-16]. The presence
17
of IR absorption bands at 1870-1875, 1615-1620, 1080-1085, 795-800,775-780, 695-
700, & 455-460 cm-1 indicate quartz in all samples and it is presented in Table 2.
The pattern of absorption in quartz can be explained by ascribing the 455cm-1
region (Si-O asymmetrical bending vibrations), the band in the region 695cm (Si-O
symmetrical bending vibrations), the bands in the region 775cm (Si-O symmetrical
stretching vibrations) and 795cm (Si-O symmetrical stretching vibrations).
For any samples, minimum four to maximum six peaks are observed.
The characteristic feature of quartz is doublet appearing at or around 800 cm-1and
780cm-1. Such a clear observation of doublet was noticed in the samples PPM, VPC
& OKM and any of these peaks was noticed in remaining samples. The peak
appearing at 695 cm-1 is most useful to determine the nature of the mineral with
regard to the structural stability. Many workers have calculated the crystallinity
index of quartz using the symmetrical bending vibration of Si-O group obtained at
695 cm-1. The 695 cm-1 is present in most of the samples indicate that quartz mineral
are well in crystalline form. Band assignments for different minerals of coastal
sediment samples are given in Table 3.
3.2. Feldspar
Around 60% of the Earth's crust is made up of feldspar; the feldspars are a
group of minerals that have similar characteristics due to a similar structure. The
general formula for feldspar can be given as WZ4O8in which W may be a Na, K, Ca,
and /or Al. Chemically the feldspar is silicates of aluminum containing sodium,
potassium, iron, calcium or barium or combinations of these elements. Feldspar is
found in association with all rock types including granite, gneiss, basalt and other
crystalline rocks and constituents of the most igneous rocks. It crystallize from
magma in both intrusive and extrusive rocks; they occur as compact minerals, as
veins, and are also present in many types of metamorphic rock. They are also found
in many types of sedimentary rocks. Feldspar weather to yield a large part of clay
found in soils. The feldspar group of minerals was analyzed by FT-IR technique and
reported by many workers [13-21]. From the Table 2, the i.r. absorption peaks
appearing at 405-410, 420-425, 425-430, 430-435, 460-465, 465-470, 535-540, 575-
18
580, 580-585, 585-590, 640-645, 645-650, 720-725, 740-745, 765-770, 785-790,
990-995, 1010-1015, 1040-1045 & 1050-1055cm-1 was assigned to feldspar mineral.
The peaks appearing at 465-470cm-1, 535-540cm-1 & 640-645 belong to Si-O-
Si bending, Si-O asymmetrical bending vibration and Al-O coordination vibration
respectively.
3.2.1. Microcline
The presence of microcline is identified by the peaks at 425-430, 460-465, 530-
535, 585-590, 640-645, 740-745 & 1050-1055 cm-1.
3.2.2. Orthoclase
The peaks at 430-435, 465-470, 535-540, 580-585, 645-650,765-770,
1010-1015 & 1040-1045cm-1 are observed for Orthoclase in the Samples.
3.2.3. Albite
The observed peaks of albite are 405-410, 420-425, 575-580, 720-725, 785-790
& 990-995cm-1.
3.3. Clay Minerals
Clay minerals are very common in fine grained sedimentary rocks such as
shale, mudstone, and siltstone and in fine grained metamorphic slate and phyllite.
Clay minerals are common weathering products (including weathering of feldspar)
and low temperature hydrothermal alteration products. Clay minerals include Kaolin
group which includes the minerals kaolinite, dickite, halloysite, and nacrite
(polymorphs of Al2Si2O5(OH)4) and Smectite group which includes dioctahedral
smectites such as montmorillonite and nontronite and trioctahedral smectites like
saponite. The presence of kaolinite and montmorillonite indicate clay minerals in
samples.
Kaolinite is a mineral with a chemical composition Al2Si2O5. It is layered
silicate mineral, with one tetrahedral sheet linked through oxygen molecules to one
octahedral sheet of alumina octahedral. Kaolinite mineral is crystallizing in the
monoclinic system and forming the chief constituent of china clay and Kaolin. It is
softly, earthy, usually white mineral, produced by weathering of feldspars. It is a
hydrous aluminum silicate commonly formed by weathering and decomposition of
rocks containing aluminum silicate compounds; feldspar is a chief source. Kaolinite
19
is the basic raw material for ceramics and large quantities are also used in the
manufacture of coated paper.
The IR absorption peaks of kaolinite are reported by many workers [22-26].
The observed peaks at 470-475, 935-940, 1030-1035, 1115-1120 & 3420-3425 cm-1
are attributed to kaolinite. The broad absorption band observed at 1030 cm-1 belongs
to Si–O stretching of kaolinite (clay mineral) [18-19].
Montmorillonite is a very soft phyllosilicate mineral that typically forms in
microscopic crystals, forming clay. Chemically it hydrated sodium calcium
aluminium magnesium silicate hydroxide(Na.Ca)x(AlMg)2(Si4O10)(OH)2.nH2O.
Montmorillonite, a member of the smectite family is 2:1 clay, meaning that it has 2
tetrahedral sheets sandwiching a central octahedral sheet. It is the main constituent of
the volcanic ash weathering product, bentonite.
The observed i.r absorption bands at 475-480, 875-880, 1640-1645 and
3440-3445 cm-1 in the spectrum of the samples suggested the presence of
montmorilinite in the samples [13, 8, 15, 16, 20]. The band typically centered at
3400cm-1 is due to O-H stretching of water molecule present in the interlayer region
of montmorillonite. The strong peak observed at 1635 cm-1 in the samples suggests
the possibility of water of hydration in the adsorbent.
3.4. Carbonate Minerals
Carbonates are commonly deposited in marine settings when the shells of dead
planktonic life settle and accumulate on the sea floor. This class also includes the
nitrate and borate minerals. Many workers have reported that i.r absorption band
appearing at 2982, 2519, 1795, 1410, 1433, 875 & 715cm-1 is assigned to calcite
[2.4-5. 7-8, 11, 16, 18, 19, 23]. The calcite shows the i.r. absorption bands appearing
at 2515, 1795, 1410, 875cm-1 & 715cm-1 in the samples. From Table 2, the IR
absorption bands at 855-860, 1455-1460, 1475-1480, & 1785-1790cm-1 are found to
be aragonite [4-5. 8, 11, 14, 19].
3.5. Organic Carbon
The weak absorption bands present at 2925-2930 and 2850-2855 cm-1 suggest
the presence of organic carbon in the samples [15-16, 20]. These bands are due to C-
20
H absorption of contaminants present in the samples. This band belongs to carbon
and oxygen double bonded linkage (C=O).
4.0. CONCLUSION
FT-IR spectroscopic analysis performed on the coastal sediment samples
taken from Pattipulam to kaipanikuppam of East coast of Tamilnadu India allowed to
identify the constituents of minerals. The FTIR study indicates presence of quartz,
microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and
organic carbon in soils. Among the various observed minerals, quartz, feldspar and
kaolinite are major and others are trace on the basis of their presence and intensities
of corresponding peaks. The performed analyses provided useful information about
the mineralogical composition of the sediments. This is a fundamental step in
gaining knowledge about the constituent of minerals. The FT-IR technique was
highly useful in identifying different minerals in sediment. The FT-IR approach with
respect to the traditional one is tremendous due to preparation.
References
1. Crompton, T.R. Determination of Metals and Anions in Soils, Sediments and
Sludges. Taylor & Francis Books Ltd, 2001. United Kingdom.
2. Ravisankar R. Application of Spectroscopic techniques for the identification
of minerals from beach rocks of Tamilnadu. EARFAM. 2009;19:272.
3. Farmer VC. The IR Spectra of Minerals. Mineralogical Society. London.
1974;182.
4. ClarenceKarr. Jr. Infrared and Raman Spectroscopy of Lunar and Terrestrial
Minerals.Academic Press: Newyork. 1974;1.
5. Pichard C, Frohlich F. Quantitative IR analysis of sediments, Example of
Quartz and Calcite determination. Revue de I InstitutFrancais du Petrole.
1986;41:6.
6. Herbert TD, Brian A, Tom, Burnett C. Precise major component
determinations in deep sea sediments using Fourier Transform infrared
Spectroscopy. Geochimica Cosmo chimica Acta. 1992;56:1759.
21
7. Benedetto GED, Laviano R, Sabbatini L, Zambonin PG. Infrared
spectroscopy in the mineralogical characterization of ancient pottery. Journal
of Cultural Heritage. 2002;3:177.
8. Ravisankar R, Senthilkumar G, Kiruba S, Chandrasekaran A, Prince Prakash
Jebakumar. Mineral Analysis of Coastal Sediment samples of Tuna, Gujarat,
India. Indian Journal of Science and Technology. 2010;3:775.
9. Bishop JL, Koeberl C, Kralik C, Frosechio H, Peter A, Englert J, Anderseen
W, Piters CM, Wharton JR. Reflectance spectroscopy and geochemical
analysis of Lake Hoare sediments, Antarctica; implications for remote sensing
of the earth and mars. Geochimica Cosmo chimica Acta. 1996;60:765.
10. Bertaux J, Frohlich F, Ildefonse P. Multi component analysis of FT-IR
spectra;Quantification of amorphous and crystallized mineral phases in
synthetic and natural sediments. Journal of Sedimentary Research.
1998;68:440.
11. Reig FB, Adelankndo JVG, Moreno MCM. FT-IR Quantitative analysis of
Calcium Carbonate Coates JP. The IR Analysis of Quartz and Asbestos.
Nelioth Offset Ltd., Chesham, England; 1977.
12. Coates JP. The IR Analysis of Quartz and Asbestos. Nelioth Offset Ltd.,
Chesham, England; 1977.
13. Ravisankar R, Rajalakshmi A, Manikandan E. Mineral Characterization of
Soil samples in and around Salt Field Area, Kelambakkam, Tamilnadu, India.
ActaCiencia Indica. 2006;XXXIIP
14. Russell JD. Infrared methods. A Hand Book of Determinative Methods in
Clay Mineralogy, Wilson, M. J.(Ed.,) Blackie and Son Ltd. New york, 11-67.
15. Ravisankar R, Kiruba S, Naseerutheen A, Chandrasekaran A, MaheswaranC.
Estimation of firing temperature of Ancient potteries of Tamilnadu, India by
FT-IR Spectroscopic technique. Der Chemica Acta. 2011;2;157.
16. Ravisankar R, Eswaran P, Rajalakshmi A, Chandrasekaran A, Dhinakaran B.
Beach rock from the South East Coast of Tamilnadu, India. A Spectroscopic
study, Advances in Applied Science. 2012;3:95
22
17. Hlavay J, Jonas K, Elek S, Inczedy J. Characterization of the particle size and
the crystallinity of certain minerals by infrared spectrophotometry and other
instrumental methods- II. Investigation on quartz and feldspar. Clay and Clay
Minerals. 1978;26:139.
18. White JL. Interpretation of infrared spectra of soil minerals. Soil Science.
1971;112:22 Ghosh SN. Infrared spectra of some selected minerals, rocks and
products. Journalof Material Science. 1978;13:1877.
19. Ghosh SN. Infrared spectra of some selected minerals, rocks and products.
Journal of Material Science. 1978;13:1877.
20. Ravisankar R, Kiruba S, Chandrasekaran A, Naseerutheen A, Seran M, Balaji
PD. Determination of firing temperature of some Ancient Potteries of
Tamilnadu, India by FT-IR Spectroscopic Technique. Indian Journal of
Science and Technology. 2010;3:1016.
21. Ravisankar R, Chandrasekaran A, Kiruba S, Senthilkumar G, Maheswaran C.
Analysis of Ancient Potteries of Tamilnadu, India by Spectroscopic
Techniques. Indian Journal of Science and Technology. 2010;3:858
22. Neog AK, Boruah RK, Sahu OP, Borah PC, Ahmed W, Boruah GD. XRD
and IR of Deopani clay. Asian. Chemical Letters. 1999;3:172.
23. Xu Z, Cornilsen BC, Popko DC, Penning WD, Wood JR, Hwang JY.
Quantitative mineral analysis by FT-IR spectroscopy. International Journal of
Vibirational Spectroscopy. 2001;5:4.
24. Crowley JK, Vergo N. Near- infrared reflectance of mixtures of kaolin group
minerals; use in clay. Clay and Clay Minerals. 1988;36:310.
25. Oinuma K, Hayashi H. Infrared study of mixed layer clay minerals, American
Minerals. 1965;50:1213.
26. Bukka K, Miller JD, Shabtai J. FT-IR study of deuteratedmontmorillonites:
structural features relevant to pillared clay stability. Clay and Clay Minerals.
1992;40:92.
23
ACOUSTICAL STUDIES ON THE EFFECT OF ELECTROLYTES ON THE
MICELLIZATION OF SODIUM CAPRYLATE AT 303.15 K
S.Arumugam1and S.Maria Antony Pragash2
1,2Post-Graduate and Research Department of Physics,
Shanmuga industries arts and science college, thiruvannnamalai.
ABSTRACT
Ultrasonic velocity, density and viscosity studies have been carried out in
aqueous solutions of sodium caprylate containing 0.1 - 0.5 M electrolytes (LiCland
KCI) in the molar concentration range of 0.05-0.50 M. These studies are carried out
in sodium caprylate concentration range of 0.05-0.50 M at a fixed frequency of
2MHz and at a fixed temperature of 303.15K. The variation of ultrasonic velocity in
aqueous solutions of sodium caprylatecontaining 0.1 - 0.5 M electrolytes (LiCl and
KCI) with the sodiumcaprylateconcentration exhibit a break at critical micelle
concentration (CMC). Experimental data have been used to estimate the adiabatic
compressibility (β), apparent molar volume (ɸv), apparent molar compressibility (ɸk)
and specific viscosity (ŋsp).The result are discussed in terms of structure making or
structure breaking effect of electrolytic solution in the mixtures .The results are
discussed in terms of formation of sodium caprylatemicelles through hydrophobic
interaction and hydrogen bonding.
INTRODUCTION
Molecular interaction in liquid mixtures has been the subject of numerous
investigation in recent past years. Effects of temperature on the micelle formation of
anionic surfactants in the presence of different concentrations of urea have been
reported by Sandeep Kumaret al.[1].Here one of the attempts is undertaken to
investigate, the effect of electrolytes such as (LiCl and KCl) on the micellization of
surfactant (sodium caprylate) in aqueous medium which is more important because
the electrolytes play the important role on surfactant.
The values of density, ultrasonic velocity, and viscosity, observed ultrasonic
absorption,adiabatic compressibility, apparent molar volume apparent, apparent
24
molar compressibility with molar concentration of sodium caprylate in aqueous and
aqueous – electrolytes (LiCl and KCI) mixtures of various compositions at a fixed
frequency of 2 MHz and fixed temperature of 303.15 K are also given in figures 1-
12. The aim our present investigation is to determine ultrasonic studies on the
effect of electrolytes (LiCl and KCI) on the micellization of sodium
caprylatein aqueous solutions at fixed frequency of 2 MHz and fixed
temperature of 303.15 k. The results are interpreted in terms of formation of sodium
caprylate(NaC)micelles in the solutions.
MATERIALS AND METHODS
The surfactant namely sodium caprylate(NaC) and electrolytes(liCl&KCl)
used in present study are of AR/BDH grade purchased from Merck specialties
private limited, India. They are used as such without further purification and all
chemical having a purity of ≥99%. Millipore water having a specific conductance of
2.3×10-6 S m-1 is used in preparing the stock solution of electrolytes and surfactant.
Aqueous solutions of surfactant containing different concentration of electrolytes of
electrolytes (0.05 - 0.50 M) are prepared by adding concentration stock solution of
electrolytes. All the measurements are carried out in the surfactant concentration of
0.05 - 0.50 M. Ultrasonic velocity and absorption studies are fixed frequency of 2
MHz in the surfactant concentration range 0.05-0.50 M. Ultrasonic velocity and
absorption measured using a digital ultrasonic pulse echo velocity meter at a fixed
temperature of 303.15 K.
The experimental part comprises of determination of density (ρ), viscosity
(ηs), and observed ultrasonic absorption (α). Using these fundamental parameters the
various other parameters such as adiabatic compressibility (β), apparent molar
volume(ɸv), apparent molar compressibility (ɸk) and specific viscosity (ηsp) can be
computed.
RESULT AND DISCUSSIONS
From the measured values of ultrasonic velocity (U), viscosity (ηs), and
observed ultrasonic absorption (α), adiabatic compressibility (β), apparent molar
25
volume (ɸv), apparent molar compressibility (ɸk) and specific viscosity (ŋsp) were
computed and shown in graphically in figures (1-12). Apparent molar volume (ɸv)
calculated from density data for aqueous solutions of NaC and aqueous sodium
caprylate (NaC) containing 0.1 - 0.5 M electrolytes (LiCl and KCl) is found to be
negative for the entire concentration range of surfactant as shown in figures 1 - 2.
Also, the values of apparent molar volume (ɸv) increases (becomes less negative)
with increase of NaC concentration for each concentration of electrolytes. The
addition of electrolytes to aqueous solutions of NaC shifts the CMC towards the
lower concentration side of surfactant. With further increase in the concentration of
electrolytes added the CMC shifts more towards lower concentration side of NaC.
The addition of electrolytes (LiCl and KCl) not only decrease the CMC of ionic
surfactants [2] by screening the electrostatic repulsion between the polar head groups
and also restrict the movement of the hydrophobic surface of the surfactant
molecules away from aqueous environments. As a result, less electrical work is
required in the formation of surfactant micelles. This is responsible for the shift of
the CMC towards lower concentration side of NaC respectively in the presence of
electrolytes. These results obtained from the present studies are in good agreement
with the observations made by Chauhanet al.[2] in aqueous solutions of SDS
containing LiCl and KCl.
From the figures 3 - 6 it can be seen that the ultrasonic velocity measured in
aqueous solution of surfactant (NaC) containing different concentration of
electrolytes increases with increasing concentration of surfactant. The Na+ ion
obtained due to the dissociation of NaC in aqueous medium may contribute towards
the increase of ultrasonic velocity by increasing cohesion in the medium by its water
structure making property.In addition the aggregation of NaC molecules with
counter ions at the interface may also increase the cohesion among water molecules
at the interface leading to an increase of ultrasonic velocity.Water molecules from
hydrogen bonds with the carboxylate group of NaC. The hydrogen bond formations
also contribute for the increase in ultrasonic velocity.The increase of ultrasonic
velocity when the concentration of NaC is increased beyond CMC may be due to the
26
aggregation of NaC molecules leading to micelle formation [3]. Above CMC,
aggregation of molecules occurs by hydrogen bonding. The formation of higher
aggregates through hydrogen bonding leads to an increase of ultrasonic velocity in
the medium.
In the present studies, the ultrasonic velocity measured in aqueous solutions
of NaC containing different concentrations of electrolytes is found to be in the order:
KCl<LiCI. This is due to the difference in the electrostriction effect produced by the
cations namely Li+ and K+ of these electrolytes in the surrounding medium. The
results obtained from the ultrasonic velocity and adiabatic compressibility studies of
the present work is in good agreement with the results of patilet al.[4] carried out in
aqueous solutions of sodium dodecyl sulphate with electrolytes.
The apparent molar compressibility (ɸk) obtained for aqueous NaC with
electrolytes in the entire concentration range of surfactant (NaC) studied are found to
be negative as shown in figures 7 - 8 for any particular concentration of each
electrolyte, the apparent molar compressibility of aqueous solutions of both
surfactant increases (become more negative) with increasing concentration of
surfactant as shown in figures 7 - 8. The negative values of apparent molar
compressibility (ɸk) indicate that three is an increase in the amount of structured
water present in the medium. This may be due to the ionic hydration of Li+, K+ ions
and hydrophobic hydration of NaC anions The increase (more negative) in the values
of apparent molar compressibility with increase in the concentration of each
electrolyte (LiCl&KCl) at a particular concentration of surfactant may be due to the
increased ionic hydration of cations of the electrolytes. These result in an increase of
internal pressure which in turn leads to lowering of compressibility of the solutions.
i.e. the solution becomes header to compress.
From the figures 9-10 the Specific viscosity in aqueous solution of
surfactant (NaC) and aqueous solutions of sodium caprylate (NaC) containing 0.1 -
0.5 M of electrolytes (LiCl and KCl) increases with increasing concentration of
surfactant.The CMC values obtained from Specific viscosity studies for aqueous
solution of surfactant containing 0.1 - 0.5 M electrolytes in agreement with the CMC
27
values obtained from molar volume. When the electrolytes are added to aqueous
surfactant solution, it disrupts the existing solvent structure and forms a new and
thermodynamically more feasible arrangement [5-7].As a result, the water molecules
are tightly bound to each other due to the more hydrophobic nature of sodium
caprylate ions and hydrophilic nature of electrolytic cations in the medium. This
invariably results in the increase of specific viscosity in the medium as observed in
the present work
The observed ultrasonic absorption (α/f2) in aqueous solutions of surfactant
(NaC) and aqueous solution of sodium caprylate (NaC) containing electrolytes
increases with increasing concentration of surfactant as shown in figures 11-12
Moreover, the observed absorption is found to be several time higher than the
classical absorption. This indicates that the observed absorption is not the observed
absorption. Water monomers present in the medium can form by hydrogen bonds
with carboxylate groups of NaC. The increase of cohesion in the solutions leads to
increase in ultrasonic absorption.When NaC is dissolved in water, it dissociated into
cation (Na+ ions) and anions (sodium caprylate). Na+ ions thus obtained restrict the
overall freedom of water molecules by its water structure making property. This
increases the cohesion among the water molecule, thus leading to increasing of
ultrasonic absorption.When electrolytes are dissolved in aqueous solutions of
surfactant (NaC) due to the dissociation of electrolytes, cations such as Li+, K+ and
Cl- anions along with sodium caprylate anions are obtained. Moreover, the ionic
hydration formed around Li+ and K+ ions also contributes towards the increased
cohesion among the water molecules in the medium leading to an increased in
observed ultrasonic absorption. In the presence of hydrophobic sodium caprylate
ions, the solvent- solvent interactions are strengthened due to strong hydrophobic
hydration. This makes the surrounding water molecules to be very closely packed;
this in turn increases the observed ultrasonic absorption in the medium.
The CMC values of aqueous NaC and aqueous solutions of sodium caprylate
(NaC) having different concentration of electrolytes(LiCl&KCl) in the order: 0.35
M for aqueous NaC0.33, 0.30, 0.27 M for aqueous with 0.1 – 0.5 M LiCl. 0.32,
28
0.28, 0.25 M for aqueous with 0.1 – 0.5 M KCl.Ultrasonic velocity, adiabatic
compressibility (β), apparent molar volume (ɸv), apparent molar compressibility (ɸk)
and specific viscosity (ŋsp).The result are discussed in terms of structure making or
structure breaking effect of electrolytic solution in the mixtures.
CONCLUSION
In the present study, apparent molar volume apparent molar compressibility
values are found to be negative in aqueous solution of Sodium caprylate and aqueous
solution of NaC with electrolytes. Ultrasonic velocity in aqueous solution of
surfactant (NaC) and aqueous solution of NaC with electrolytes increases with
increasing concentration of NaC and electrolytes. The apparent molar volume (ɸv) is
negative values with addition of each of 0.1- 0.5 M (LiCl and KCl)to aqueous
solution of NaC, the CMC shifts towards lower concentration side. The extent of
shifting of CMC towards lower concentration side of surfactant by the anions of
electrolytes depends on degree of counter ion binding to the micelles. The observed
ultrasonic absorption in aqueous solution of sodium caprylate with electrolytes is due
to the ionic and hydrophobic hydration in the medium. Formation of hydrogen bonds
between water molecules and the carboxylate groups of surfactant also contributes
for the observed increase in ultrasonic absorption.
Figure – 1 Figure – 2
0.2 0.3 0.4 0.5 0.6 0.7-0.16-0.15-0.14-0.13-0.12-0.11-0.10-0.09-0.08-0.07-0.06-0.05-0.04-0.03-0.02-0.010.00
0.35 M
0.32 M0.27 M
0.25 M
App
aren
t mol
arvo
lum
e (
v) m
3 mol
-1
Square root of molar concentration of sodium caprylate (C)1/2mol dm-3
NaC+waterNaC+water+0.1 M kClNaC+water+0.3 M kClNaC+water+0.5 M kCl
0.2 0.3 0.4 0.5 0.6 0.7
-0.050
-0.045
-0.040
-0.035
-0.030
-0.025
-0.020
-0.015
-0.010
-0.005
0.33 M
0.27 M
0.30 M
0.35 M
App
aren
t mol
arvo
lum
e (
v) m3 m
ol-1
Square root molar concentration of sodium caprylate (C)1/2 mol dm-3
NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl
29
0.0 0.1 0.2 0.3 0.4 0.51520
1525
1530
1535
1540
1545
1550
1555
1560
1565
0.28 M
0.25 M
0.32 M
0.35 M
Ultr
ason
ic v
eloc
ity
(U)
m s-1
Molar concentration of sodium caprylate (c) mol dm-3
NaC+waterNaC+water+0.1 M KClNaC+water+0.3 M KClNaC+water+0.5 M KCl
0.0 0.1 0.2 0.3 0.4 0.51520
1525
1530
1535
1540
1545
1550
1555
1560
1565
1570
1575
0.30 M0.27 M
0.33 M
0.35 M
Ultr
ason
ic v
eloc
ity (U
) m s-1
Molar concentration of sodium caprylate concentration (C) mol dm-3
NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl
Figure – 3 Figure– 4
Figure – 5 Figure – 6
Figure – 7 Figure – 8
0.0 0.1 0.2 0.3 0.4 0.54.05
4.10
4.15
4.20
4.25
4.30
0.28 M
0.25 M
0.35 M
0.32 M
Adi
abat
ic co
mpr
essib
ility
(s)
X 1
0-10 N
-1 m
2
Molar concentration of sodium caprylate (C) mol dm-3
Nac + waterNaC + water + 0.1 M kClNaC + water + 0.3 M kClNaC + water + 0.5 M kCl
0.0 0.1 0.2 0.3 0.4 0.54.024.044.064.084.104.124.144.164.184.204.224.244.264.284.304.324.34
0.27 M
0.30 M
0.33 M
0.35 M
Adi
abat
ic co
mpr
essib
ility
(s)
X 1
0-10 N
-1 m
2
Molar concentration of sodium caprylate concentration (c) mol dm-3
NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl
0.2 0.3 0.4 0.5 0.6 0.7-8.5-8.0-7.5-7.0-6.5-6.0-5.5-5.0-4.5-4.0-3.5-3.0-2.5-2.0-1.5-1.0-0.50.00.5
0.25 M
NaC + WaterNaC + water + 0.1 M KClNaC + water + 0.3 M KClNaC + Water + 0.5 M KCl
0.28 M0.32 M
0.35 M
App
aren
t mol
ar co
mpr
essib
ility
(k)
X 1
0-8 m
3 mol
-1 P
a-1)
Square root of molar concentration of sodium caprylate (C)1/2mol dm-3
0.2 0.3 0.4 0.5 0.6 0.7
-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
0.35 M
0.33 M
0.30 M
0.27 M
App
aren
t Mol
ar c
ompr
essi
bilit
y (
v) X
10-8
m3 m
ol-1 P
a-1
Square root 0f molar concentration of sodium caprylate (c)1/2mol dm-3
NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl
30
Figure – 9 Figure – 10
Figure – 11 Figure – 12
REFERENCES
1.Sandeep Kumar, PunamYadav, Dinkar Malik and Vijai Malik InternationalJournalofTheoretical &AppliedSciences6(1): 43-49, (2014)
2. L.zang,P.Somasundram,C.Maltesh,Langmuir 12 (1996)2371.
3. M.K.Rawat,Sangeeta, Ind .J.Pure& appl.Phys.46(2008)187. 4 .D.G.Oakenfull,L.R. Fisher,J.phys.Chem.81(1977)1838 5. C.S.Patil, B.R.Arbad,Asian J.Chem.15(2003)655. 6. A.P.Mishra, Ind.J.Chem.43A(2004)730. 7. Monalisa Das, S.Das, A.K.Patnaik, J.phys.Sci.24 (2013)37.
0.2 0.3 0.4 0.5 0.6 0.70.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.28 M
0.25 M
0.32 M
0.35 M
Spec
ific
visc
osity
(sp
/ C1/
2 )
Square root of molar concentration of sodium caprylate (c)1/2 mol dm-3
NaC+waterNaC+water+0.1 M KClNaC+water+0.3 M KClNaC+water+0.5 M KCl
0.2 0.3 0.4 0.5 0.6 0.7
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.30 M
0.27 M
0.33 M 0.35 M
Spec
ific
visc
osity
(sp
/ c1/
2 )
Square root of molar concentration of sodium caprylate (c)1/2 mol dm-3
NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl
0.0 0.1 0.2 0.3 0.4 0.5
2050
2100
2150
2200
2250
2300
2350
2400
2450
2500
2550
0.35 M
0.32 M
0.25 M
0.28 M
Obs
erve
d ul
trra
soni
cabs
orpt
ion
( /
f2 ) X 1
0-15
Np
m-1 s2
Molar concentration of sodium caprylate (C) mol dm-3
NaC + waterNaC + water + 0.1 M KClNaC + water + 0.3 M KClNaC + water + 0.5 M KCl
0.0 0.1 0.2 0.3 0.4 0.5
2050
2100
2150
2200
2250
2300
2350
2400
2450
2500
2550
2600
2650
2700
2750
0.27 M
0.30 M
0.33 M
0.35 M
Obs
erve
d ul
tras
onic
abs
orpt
ion
(f2 ) X
10-1
5 Np
m-1 s2
Molar concentration of sodium caprylate (c) mol dm-3
NaC+waterNaC+water+0.1 M LiClNaC+water+0.3 M LiClNaC+water+0.5 M LiCl
31
ULTRASONIC STUDIES ON THE EFFECT OF ALCOHOLS ON THE
MICELLATION OF LITHIUM DODECYL SULPHATE
IN AQUEOUS SOLUTION
G. Lakshiminarayanan1 and A.Anithadevi2
1,2 Post-Graduate and Research Department of Physics
Shanmuga Industries Arts and Science College,Thiruvannamalai.
Abstract
Acoustical studies are undertaken in required amount of LDS with the
addition of various proportions of alcohols [ME, ET] at various concentrations
ranging from 5mM to 13mM at 303.15 K. From the measured values of velocity,
density, and viscosity various other parameters such as compressibility, free length,
free volume and internal pressure are calculated and reported. The results indicate
that the ultrasonic velocity of ethanol is lightly higher than methanol for all aqueous
and aqueous alcoholic mixture because of due to their chain length difference.
Keywords: Ultrasonic velocity, Compressibility, LDS, Free length
INTRODUCTION
Amphiphilic molecules like surfactants exhibit several special properties,
such as critical micelle concentration (CMC), aggregation number, size and shape of
the micelle and degree of micelle dissociation, because of their ability to undergo co-
operative and non-co-operative aggregation in aqueous system. Such properties are
modified by the addition of substances such as, salts or non electrolytes (alcohols,
urea, amine etc.)[1-4].These additives can affect in many ways to delicate balance of
hydrophilic and hydrophobic interactions of micelle forming surfactants.
Considerable attention has been paid in recent years to the influence of alcohols on
ionic micellar structures, partly because they are the co-surfactants most commonly
employed in the preparation of micro emulsions. In the present investigation
ultrasonic method is used for obtaining dynamic information and reactions occurring
in the aqueous micellar solutions of Lithium dodecyl sulphate in the presence of
alcohols.
EXPERIMENTAL TECHNIQUES
The experimental solutions are prepared by the required amount of Lithium
dodecyl sulphate is dissolved in de ionized water for the preparation of concentration
32
range of 3mM - 12mM. The 5%, 10%, 15% and 20% of Methanol (ME), Ethanol
(ET) with Lithium dodecyl sulphate (LDS) in aqueous solutions are prepared in the
concentration range of 3mM - 12mM. The velocity of ultrasonic waves in the
solution have been measured using digital ultrasonic pulsed echo velocity meter
(model no: VCT – 70A, Vi Micro Systems Pvt. Ltd, Chennai) work at a fixed
frequency of 2 MHZ and fixed temperature of 303.15k. The values of density and
shear viscosity of different concentrations were measured using specific gravity
bottle and Ostwald’s viscometer respectively. All the measurements were carried out
at 303.15 K by maintaining the temperature constant by circulating water from a
thermostatically controlled water bath.
COMPUTATIONS OF PARAMETERS
Adiabatic compressibility (βs), intermolecular free length (Lf), free volume
(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),
respectively.
βs = 1/C2ρ (1)
Lf = KT βs 1/2 (2)
Vf = (M C / K η)3/2 (3)
πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)
where, c is ucltrasonic velocity, ρ is density, KT is temperature dependant constant,
M is effective molecular weight, K is constant for liquids, b is constant, T is
temperature.
RESULT AND DISCUSSION
In the present study, the ultrasonic velocity, density and viscosity
measurements were carried out in aqueous solution of LDS with addition of alcohols
[Methanol and Ethanol] at different concentrations. The values of velocity (U),
density (ρ) and viscosity (η) with molar concentration of lithium dodecyl sulphate in
aqueous and aqueous – alcoholic mixtures of various compositions measured for a
fixed frequency of 2 MHz and fixed temperature of 303.15 K. The values of
Adiabatic Compressibility, Free length, Free Volume and Internal Pressure with
33
molar concentration of lithium dodecyl in aqueous and aqueous – alcoholic mixtures
of various compositions at a fixed frequency of 2 MHz and fixed temperature of
303.15K.
Ultrasonic velocity studies of lithium dodecyl sulphate in aqueous solutions
The variations of ultrasonic velocity against concentration of lithium
dodecyl in aqueous solution are given in Figs. 1 & 2. The measured ultrasonic
velocity increases with increasing concentration of lithium dodecyl sulphate in
aqueous solutions and exhibits sharp break at a particular concentration is known as
Critical Micellar Concentration (CMC) which is confirmed by Chanchal das etal [5] .
The increase in ultrasonic velocity can be explained as follows. 1) When the lithium
dodecyl sulphate is added in aqueous solvent, lithium dodecyl dissociates Na+ ions
and dodecyl sulphate ions. Na+ ion restrict the mobility of the water
molecules.2)The lithium dodecyl sulphate ions making hydrogen bond with water
molecules.3) The micelle formation in aqueous solution of lithium dodecyl sulphate
and higher aggregation leads to increase in velocity beyond the CMC.All the above
mentioned effect contributes the increase in velocity before and after CMC.
The measured ultrasonic velocity increases with increasing concentration of
lithium dodecyl sulphate in aqueous – alcoholic solvent (5-20%V/V of ME &ET)
mixtures of solution and exhibits sharp break at a particular concentration of lithium
dodecyl sulphate (i.e.)., CMC as shown in Fig 1. The increase in ultrasonic velocity
is due to the alcoholic solvents act as a structure breaker in aqueous lithium dodecyl
sulphate. So,this is leads to restricting the mobility of the water molecules by lithium
ions. The micelle formation in aqueous-alcoholic solution of lithium dodecyl
sulphate and higher aggregation leads to increase in velocity after CMC of solution.
In addition to average dielectric constant of lithium dodecyl sulphate in the solution
also contributes increase in ultrasonic velocity. The velocity observed in aqueous-
alcoholic solvent at particular compositions (volume by volume) in the order:
Velocity of 5% ME mixture < Velocity of 10 % ME mixture < Velocity of 15 % ME
mixture < Velocity of 20 % ME mixture.
Similarlly, the same explanation observed for LDS with aqueous-ethanol systems.
34
In addition, the presence of alcoholic (Co – Solvent) affect the compressibility
of the medium by disrupting the ordered water structure present around the
hydrophobic and hydrophilic surfaces of LDS molecules in order to form hydrogen
bonding with water molecules. This strengthens the aqueous – alcohol solvent
interaction by the way of releasing structured water present around the ions of
lithium dodecyl sulphate. This might be responsible for the decreasing of
compressibility (Fig.5&6) by addition of alcohols.
From the figure 1, it is observed that when the 5% V/V of methanol is added
to the aqueous solution of lithium dodecyl sulphate, the CMC of aqueous solution of
lithium dodecyl sulphate shifted towards the higher concentration side (8.4 mM).
This is due to the lowering of the average dielectric constant of the medium because
of the dielectric constant of water is greater than methanol.
Similarly, when the 10-20% V/V of methanol is added to the aqueous solution
of lithium dodecyl sulphate the CMC of aqueous solution of lithium dodecyl
sulphate shifted towards the higher concentration side in the order of (8.9 mM), (9.5
mM), (10 mM), respectively. For ethanol systems observed CMC valuesin the
order: 8.7, 9.3, 9.8 and 10.5Mm, respectively.
Viscosity studies of lithium dodecyl sulphate in aqueous and aqueous –
alcoholic mixtures:
The variations of viscosity are shown in Figs. 3 & 4. The ultrasonic viscosity
increases with increasing concentration of lithium dodecyl sulphate in all the
systems are studied. This is due to the increasing viscous force within the medium.
So this leads to further increasing of ultrasonic viscosity with increasing
concentration of lithium dodecyl sulphate . .
Free length of lithium dodecyl sulphate in aqueous and aqueous – alcoholic
mixtures:
The variation of ultrasonic velocity in a solution depends on the
intermolecular free length on mixing. On the basis of a model for sound propagation
proposed by Eyring and Kincaid et al [6]. Ultrasonic velocity increases on
decreasing of free length and vice versa. Intermolecular free length is a predominant
35
factor in determining the variation of ultrasonic velocity in fluids and their solutions.
In the present investigation, it has been observed that intermolecular free length
decreases linearly on increasing concentration of lithium dodecyl sulphate in
aqueous and aqueous – alcoholic mixtures and exhibits sharp break at CMC as
shown in Figs.7 & 8.
This indicates significant interaction between solute – solvent molecules,
solvent – solvent molecules and suggesting ionic hydration of solvent molecules on
solute. As expected, adiabatic compressibility decreases with increasing
concentration of lithium dodecyl sulphate in all aqueous – alcoholic mixtures and
may be due to their increasing larger portion of solvent molecules being
electrostricted and the amount of bulk solvent decreases.
Free Volume of lithium dodecyl sulphate in aqueous and aqueous – alcoholic
mixtures:
The variations of free volume against concentration of lithium dodecyl
sulphate in aqueous and aqueous – alcoholic mixtures are shown in Figs. 9 & 10.
In aqueous solutions of lithium dodecyl sulphate , the free volume decreases with
increasing concentration of lithium dodecyl sulphate . This observation gives the
information of solvent molecules accommodate around the solute. Therefore, the
further increasing of concentration of lithium dodecyl sulphate suggested the
increase of volume in the solution. So the corresponding free volume decreases.
The above explanation theory is applicable for all the aqueous and aqueous –
alcoholic mixtures of lithium dodecyl sulphate solution.
Internal Pressure of lithium dodecyl sulphate in aqueous and aqueous –
alcoholic mixtures:
The internal pressure is the most important deciding factor for aqueostical
studies. In the present studies, the variation of internal pressure against the
concentration of in aqueous and aqueous – alcoholic mixtures as shown in Figs.
11 & 12. The internal pressure increases with increasing concentration of lithium
dodecyl sulphate in all the systems are studied. This suggests that there is a
significant interaction between the solute and solvent molecules. So the internal
36
0.004 0.006 0.008 0.010 0.012 0.0141490
1495
1500
1505
1510
1515
1520
1525
1530
1535
1540
1545
1550
Ultr
ason
ic v
eloc
ity c
(m s
-1 )
Molar concentration of LDS X ( mol dm-3)
water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS
0.004 0.006 0.008 0.010 0.012 0.014
1500
1510
1520
1530
1540
1550
1560
1570
1580
1590
Ultr
asoi
c ve
losi
ty C
(ms-1
)
Molar concentration of LDS X (mol dm-3)
water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS
0.004 0.006 0.008 0.010 0.012 0.014
7
8
9
10
11
12
13
14
15
visc
osity
(10
-4 N s
m-2 )
Molar concentration of LDS x ( mol dm-3)
water+LDS water+5% MT+ LDS water+10% MT+ LDS water+15% MT + LDS water+20% MT + LDS
0.004 0.006 0.008 0.010 0.012 0.014
7
8
9
10
11
12
13
14
15
16
17
18
19
Visc
osity
(
10-4
N s
m-2)
Molar concentration of LDS X (mol dm-3)
water+ LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS
pressure increases for further increasing of concentration of lithium dodecyl
sulphate in aqueous and aqueous – alcoholic mixtures.
CONCLUSION
In the present study, the ultrasonic Velocity, Density, Viscosity and Internal
pressure increases whereas Adiabatic Compressibility, Free length and Free Volume
decreases with increasing concentration of lithium dodecyl sulphate in aqueous
and aqueous – alcoholic (ME & ET) mixtures. Ultrasonic velocity of Ethanol is
slightly higher than Methanol for all aqueous and aqueous – alcoholic mixtures
because of due to their chain length difference.
The CMC values are obtained in aqueous and aqueous – alcoholic (ME & ET)
mixtures of various compositions of concentration of lithium dodecyl sulphate
solutions. The higher CMC values in aqueous – Ethanol mixtures for various
composition compared to aqueous – Methanol mixtures of various composition of
concentration of lithium dodecyl sulphate . This is due to the average dielectric
constant modification in aqueous – alcoholic (ME & ET) mixtures of lithium
dodecyl sulphate solutions.
Figure-1
Figure-3
Figure-2
Figure-4
37
0.004 0.006 0.008 0.010 0.012 0.0141.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
1.65
1.70
Inte
rnal
pre
ssur
e
( 1
08 pas
cal)
Molar concentration of LDS X (mol dm-3)
water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+ LDS water+20% MT+LDS
0.004 0.006 0.008 0.010 0.012 0.0141.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS
Inte
rnal
pre
ssur
e i
(108 p
asca
l)
Molar concentration of LDS X (mol dm-3)
0.004 0.006 0.008 0.010 0.012 0.0143.4
3.6
3.8
4.0
4.2
4.4
4.6
Adi
abat
ic c
ompr
essi
bilit
y
(1
0-10 N
-1 m
-2)
Molar concentration of LDS X (mol dm-3)
water+ LDS water+5% MT +LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS
Figure-5
0.004 0.006 0.008 0.010 0.012 0.0143.70
3.75
3.80
3.85
3.90
3.95
4.00
4.05
4.10
4.15
4.20
4.25
4.30
Free
leng
th L
f ( 1
0-11 m
)
Molar concentration of LDS X ( mol dm-3)
water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS
Figure-7
0.004 0.006 0.008 0.010 0.012 0.014
0.550.600.650.700.750.800.850.900.951.001.051.101.151.201.251.301.35
Free
vol
ume
Vf
(10-6
m3 )
Molar concentration of LDS X (mol dm-3)
water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS
Figure-9
0.004 0.006 0.008 0.010 0.012 0.014
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
Adi
yaba
tic c
ompr
essa
bilit
y
s ( 10
-10 N
-1 m
-2)
Molar concentration of LDS X (mol dm-3)
water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS
Figure-11
0.004 0.006 0.008 0.010 0.012 0.0143.4
3.5
3.6
3.7
3.8
3.9
4.0
4.1
4.2
4.3
Fre
e le
ngth
(Lf)
x10-1
0 m
Molar concentration of LDS (X) mol dm-3
water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS
Figure-6
0.004 0.006 0.008 0.010 0.012 0.014
0.4
0.6
0.8
1.0
1.2
Fre
e vo
lum
e (V
f) 10-6
m3
Molar concentration of LDS (X) mol dm-3
water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS
Figure-8
Figure-10
Figure-11
Figure-12
38
. References
1) M.S. Santosh, D. Krishna Bhat *, Aarti S. Bhatt, J. Chem.
Thermodynamics, 42, 742 (2010)
2) Ryszard Zieli´nski, Journal of Colloid and Interface Science, 235, 201
(2001)
3) Muhammad Sarwar Hossain , Tapan Kumar Biswas a, Dulal Chandra
Kabiraz , Md. Nazrul Islam ,Muhammad Entazul Huque, J. Chem.
Thermodynamics 71 6 (2014).
4) S. Chauhan , Kundan Sharma, J. Chem. Thermodynamics 71 (2014) 205–
211
5) Chanchal Das & Dilip K Hazra Indian J. CHEM vol. 44A,1793 (2005).
6) Nikam P.S. & Mehdi Hasan, J.Chem.Eng.Data, 165, 33 (1988)
39
Growth and characterization of morpholinium perchlorate
A. Arunkumar , P. Ramasamy
Department of Physics, Agni College of Technology, Chennai – 600 130
SSN Research Center, SSN College of Engineering, Kalavakkam- 603 110,
Tamilnadu, India
Corresponding author: [email protected]
Abstract. Morpholinium perchlorate (MP) has been synthesized and single
crystals were successfully grown for the first time by the slow evaporation
solution growth technique at room temperature. The cell parameters of grown
crystal were confirmed by single crystal X-ray diffraction analysis and it
belongs to the noncentrosymmetric space group P212121. The grown crystals
were characterized by HRXRD and UV-Vis NIR transmission analysis. The
optical nonlinearity of MP was investigated at 532 nm using 7 ns laser pulses,
employing the open aperture Z-scan technique.
Keywords; Optical properties
INTRODUCTION
Nowadays great attention has been devoted to synthesizing new organic
materials and their single crystal crystals due to their potential applications in second
and third harmonic generation, difference frequency generation, electro-optic
modulator, THz wave generation etc.,. The organic crystal can offer a highly aligned
and stable orientation of NLO chromophores in the crystal lattice. Numerous
attempts have been made to find new organic compounds with large nonlinear
optical susceptibility. Generally organic materials contain donor and acceptor groups
positioned at either end of a suitable conjugation path. Extension of benzene
derivatives has permitted an increase in the number of π electrons as well as their
delocalization length, so as to lead to remarkable enhancement in
hyperpolarizability. The large π delocalization length has been recognized as a factor
leading to large third order nonlinearity [1].In this series efforts were made to grow
MP crystals from solution in order to study their properties. Molecular ionic simple
40
complex crystals like perchlorate with Morpholine (of ratio 1:1), shows nonlinear
optical physical properties unique to the crystal structure. In the present investigation
we report the synthesis, structure and optical properties of MP.
Synthesis and Crystal Growth
Perchloric acid and morpholine were employed for the synthesis of the title
compound MP using ethanol and water. Dissolving perchloric acid in an analar grade
morpholine results in a white crystalline precipitate. Then the precipitate is allowed
to dry. The dried salt was collected and used for the further growth of MP. The
synthesized material was purified by repeated recrystallization process. The dried
precipitate was dissolved using the same solvent. But the crystallization did not
occur in this solution as it has high viscosity and low pH value. The solubility test
can be performed to choose the solvent for crystal growth. The solubility
experiments were carried out several times at temperatures 30-45˚C in the constant
temperature bath with an interval of 5˚C for various solvents such as acetone,
methanol, ethanol and mixed solvents. MP is highly soluble in acetone solvent. The
obtained dried precipitate was dissolved using acetone and then allowed to evaporate
at room temperature to yield the crystalline powder salt of MP.
The well-defined single crystals of MP were harvested from mother solution after a
growth period of 45 days. Photograph of as grown crystal is shown in
FIGURE 1.
Characterization
The grown crystals were subjected to X-ray diffraction studies. The unit cell
parameters and the crystal structure were determined from single crystal X-ray
diffraction studies. The structure was partially resolved in centrosymmetric space
group Pnma with half anions and cations in the asymmetric form and with high R –
value. But the systematic absent reflections show the absence of Pnma symmetry.
Hence the structure is refined finally in P212121 space group. The present unit cell is
indexed to a standard setting of a = 8.2802(4) Å, b = 9.7730(6) Å, c =
9.5591(5) Å and V = 773.55(7) Å3.The crystalline perfection of the grown crystals
was characterized by HRXRD and rocking curve is show in FIGURE 2. The angular
separation between the two peaks gives the tilt angle α. The tilt angle for the very
low angle boundary is 13 arc sec with respect to the main crystal block. The FWHM
41
(full width at half maximum) of the main peak and the boundary are respectively 17
and 12 arc sec. The low FWHM values of main crystal and the very low angle
boundary indicate that the crystalline perfection of the specimen is quite good. The
UV-vis-NIR spectrum is studied by Perkin-Elmer Lambda35 spectrometer with a
MP single crystal of 2 mm thickness in the range of 200-1100 nm. MP crystals
present a cut off wavelength at 215 nm with 50% transmission in the visible region
and near infrared region. the absorption at 279 nm was due to the promotion of an
electron from a ‘non-bonding’ (lone-pair) n orbital to an ‘anti-bonding’ π
orbital designated as π* (n → π*) and no characteristic absorption was observed in
the entire visible region.
FIGURE 1. Photograph of as grown
MP crystal.
FIGURE 2. Rocking curve of MP
Z-scan Measurements
An intense laser beam of 532 nm and 7 ns pulse width is split by means of a
beam splitter, and a fraction of the beam is sent to a reference photo detector where
the beam under-fills the active area of the diode. The remainder of the beam sent
through a “thin” sample is translated through the beam waist using a motorized
translation stage, after that an aperture (iris) clips roughly half of the beam intensity.
After the aperture, an open photo detector detects the remainder of the beam passing
through the iris [2]. The output of both photodiodes is sent to a dual channel energy
ratio meter interfaced to a PC.
The open-aperture Z-scan curve obtained for MP is shown in FIGURE 3. As
the sample is translated through the focal region of the beam, the open detector
measures the total transmitted intensity while the irradiance at the sample is
changing as the sample is translated, any deviation in the total transmitted intensity
must be due to multi-photon absorption. In the limit multi-photon effects are limited
42
to two-photon absorption [3]. The value of the effective two-photon absorption
coefficient is calculated using best - fit curve for the Z- scan data and is found to be
25.02 mm/GW.
FIGURE 3. Open aperture Z-scan
The estimated third order susceptibility (χ(3)) values of MP crystal is 7.185 x10-9
(esu).
Table 1. Calculated Nonlinear absorption coefficient
Conclusion
MP has been synthesized and single crystals were grown by slow evaporation
solution growth method. The cut off wavelength is 215 nm. The two photon
absorption coefficient and third order nonlinear optical susceptibility were calculated
by Z-scan technique which affirms that MP exhibits the nonlinear optical properties.
References
1. J. J. Wolff, F. Siegler, R. Matschiner, R.Wortmann,
Angew. Chem., Int. Ed. 39 (2000) 1436-1439.
2. M.Sheik-Bahae, P. Mukherjee, H.S. Kwok , J. Opt.
Soc. Am. B. 3, (1986) 379-385
3. Mikhail S. Grigoriev, Konstantin E. German and Alesia
Ya. Maruk, Acta Cryst. E64, (2008) – 390.
Input
Laser
Power
Density
(MW/mm2)
Leff
(mm)
'q'
value
from
fit
"β"
(mm/GW)
60.47 0.866 1.3103 25.02
43
Growth, Structural, spectroscopic, thermal and hardness studies of
Cesium Sulfamate single crystal
S.Rafi Ahamed1* and P.Srinivasan2
1Department of Physics, Krishnasamy College of Engineering and Technology,
Cuddalore – 607109, India
2 Department of Physics, University College of Engineering, Panruti – 607308,
India
Abstract:
Single crystals of a new semi-organic optical material of Cesium Sulfamate (CS)
have been grown by slow evaporation technique. The grown crystals were subjected
to single crystal X-ray Diffraction analysis for determining its lattice cell parameters
and its structure. The vibrational frequencies of various functional groups in the
grown crystals have been derived by FTIR analysis. The thermal studies were
performed to know the thermal behaviour. The mechanical behaviour of the grown
crystals was studied using Vicker’s Microhardness tester.
Key words: Crystal growth, Single crystal XRD, Powder XRD, Thermal Analysis,
FTIR, UV, Microhardness.
1. Introduction:
The crystals of a ANH2SO3-type consist of monovalent cations (A+ = Li+ , Na+ , K+ ,
Rb+ , Cs+ , Ag+ , NH4 + , C(NH2)3 + or (CH3)3NCH2COOH+ ) and sulfamate anions
[NH2SO3] - [1-15]. The crystal systems, space groups, lattice parameters, and elastic
constants of these crystals at room temperature have been listed in the paper as
reported by Haussühl and Haussühl [1]. It is confirmed from these data that three
crystals containing larger cations, such as A+ =Cs+ , C(NH2)3 + ,
(CH3)3NCH2COOH+ , are of monoclinic system, and other crystals are of
orthorhombic system. The melting points and fusion enthalpies for the crystals
containing the cations (A+ =Na+ , K+ , Rb+ , Cs+ , Tl+ , NH4 + ) have been
reported by Budurov and Tzolova [2]. Moreover, it has been found that KNH2SO3
and NaNH2SO3 crystals undergo phase transitions at 437.9 K with a transition
enthalpy ΔH of 4.9 kJ/mol and at 456.0 K with ΔH of 1.9 kJ/mol, respectively [3].
44
Recently, it has been reported by the measurements of DSC and elastic constants that
the KNH2SO3 crystal also undergoes another phase transition at 350 K [4].
In the recent period, search for new Non Linear Optical (NLO) materials has
escalated because of their applications like Second Harmonic Generation (SHG),
frequency mixing, electro optic modulation, optical parametric oscillation, etc.
[1].Nonlinear Optical (NLO) materials are attracting a great deal of attention due to
their applications in optical devices, such as optical switches, optical modulators,
optical communications, optical data storage and etc [2-3].
In search of new frequency conversion materials, recent interest focussed in semi-
organic materials due to their large nonlinearity, high resistance, too large induced
damage, low angular sensitivity and good mechanical hardness [4-5]. Hitherto a
series of structure determinations of the sulfamates of type A [NH2SO3] with
monovalent cations A = H, Na, K, Rb, Ag, NH4, C(NH2)3 (guanidinium) and
(CH3)3NCH2COOH (betaine) are described in literature. From a crystallographic
point of view all Sulfamate can be divided in two main series. Species with large
cations (A = Na, Rb, C(NH2)3 and (CH3)3NCH2COOH) possess monoclinic
symmetry (SCHREUER,1999). All other compounds crystallize orthorhombically.
Most of the orthorhombic sulfamates have centrosymmetric structures [6-7]. This
paper defines the crystal structure of Cs[NH2SO3]. This has been investigated by the
FTIR studies, its crystalline nature is studied by the single crystal XRD and powder
XRD. Thermal stability of the sample was tested using differential scanning
calorimetry and thermo gravimetry analysis respectively. The mechanical behavior
of the grown crystals was studied using Vicker’s Microhardness tester.
2. Experimental Procedure
2.1 Synthesis of material
Cs[NH2SO3] was synthesized by reaction of stoichiometric portions of sulfamic acid
H[NH2SO3], dissolved in deionised water, and Cesium carbonate. Single crystals of
optical quality were grown from aqueous solution by controlled evaporation over a
period of months. The reaction shown below
2 H [ NH2SO3] + Cs2CO3 2 Cs [ NH2SO3] + H2CO3
45
Good quality single crystals with well defined morphology were extracted. The
extracted single crystals of Cesium Sulfamate are presented in figure 2.
Fig.1: Grown crystals by slow evaporation method
2.2. Characterization Technique
The harvested single crystal has been analyzed by different instrumentation methods
in order to check its suitability for device fabrication. The unit cell dimensions and
space group of cesium sulfamte were obtained using a single crystal X-ray
diffractometer. Lattice parameters were calculated from 258 reflections. And also the
Powder X-ray diffraction analysis has been carried out for the as grown specimen of
Cesium Sulfamate . The presence of functional groups was identified from the
Fourier transform infra-red (FT-IR) spectral analysis. Thermal stability of the
sample was tested using differential scanning calorimetry and thermo gravimetry
analysis respectively. The mechanical behavior of the grown crystals was studied
using Vicker’s Microhardness tester.[8]
3. Result and Discussion:
3.1 Structural Determination:
The main structural features of Cesium Sulfamate are discrete [NH2SO3] - anions
linked by tetrahedral coordinated Cs+
cations (Fig.2).
Fig. 2: Projection parallel to the b r axis
illustrating the linking of the [LiO4]
46
tetrahedra chain via sulfamate groups [NH2SO3] and a system of hydrogen bonds in
Cs[NH2SO3]
The Lattice structure of Cesium Sulfamate is shown below:
Fig.3: Surrounding of Cesium with two neighbouring 6-fold rings and atomic
numbering scheme. All atoms are shown as 50% ellipsoids.
The Sulfamate groups are linked via Cesium cations. Both symmetrically
independent Cs atoms are surrounded tetrahedrally. Both tetrahedral [Cs(1)O4] and
[Cs(2)O4] shows the slight distortion from idealized geometry. Then by connecting
the neighbouring tetrahedral chains via Sulfamate groups to form a three-
dimensional framework. A system of weak hydrogen bonds N-H….O increases the
stability of the structure. At room temperature Cs(NH2SO3) crystallizes monoclinic
with the space group of P21/c .
Fig. 4: Unit cell Crystal Structure of Cs [ NH2SO3]
3.2 FTIR Spectroscopic analysis:
The vibrational measurement was carried out at room temperature. Fourier transform
infrared spectrum was obtained from Cesium Sulfamate pellet on a Perkin Elmer
47
Spectrum FT-IR spectrometer [9]. Figure – 4 shows the IR spectra of Cesium
Sulfamate crystal in the range 450-4000cm-1.
C:\Program Files\OPUS_65\MEAS\CUDDALORE SAM 1 7 1 14.0 CUDDALORE SAM 1 7 1 14 Instrument type and / or accessory 07/01/2014
3244
.51
3050
.82
2860
.44
2384
.47
2310
.72
2111
.72
1989
.77
1678
.40
1637
.48
1607
.23
1555
.92
1419
.63
1325
.55
1122
.63
1066
.06
927.
91
860.
20
100015002000250030003500Wavenumber cm-1
8688
9092
9496
9810
0
Tran
smitt
ance
[%]
Page 1/1 Fig-5: shows the IR spectrum for Cesium sulfamate
Assignments were made on the basis of relative intensities, magnitudes of the
frequencies and from the literature data. The wave numbers 1122.63 Cm-1, 1066.06
Cm-1 region are assigned on NH2 stretching. It confirms the presence of amine
group. The presence of sulfonyl group is confirm from the peak values 1678.40
Cm-1, 1637.46 Cm-1 , 1607.23 Cm-1 and 1555.92 Cm-1 regions. Also, there is no any
observation at the range of 3500 Cm-1, it shows the absence of –OH group. Thus,
the disappearance of –OH peak indicate the formation of Cesuim Sulfamate. The
observed wave numbers and the proposed assignments are listed in Table 1.
Table: 1, Wave number of absorption peaks in FTIR spectrum and their assignments
of Cs [ NH2SO3]
FTIR Cm-1 Mode Assignments
1122.63
1066.06 NH2 stretching
1678.40
1637.46
1607.23
1555.92
S-O, S=O stretching
sulfonyl group
3500 No peaks found
48
3.3. X-ray diffraction analysis:
3.3.1 Single Crystal Diffraction studies:
The Unit cell Parameters of the Cesium Sulfamate crystal are measured from a single
crystal diffractometer. The crystal parameters, Cell volume, system and space group
found to be in well agreement with that of reported values (Scheruer in 1992). The
crystal data of cesium sulfamate is presented in table.2 below.
Table 2: crystal data for Cs(NH2SO3) crystal:
Cesium Sulfamate
Molecular
Formula Determined from single
crystal XRD in present
studies
From Literature
(Phase transitions in Cesium
Sulfamate - Schreuer in
1992)
a= 8.20 A° a= 8.250 A°
b = 7.63 A° b = 7.6246 A°
c = 8.41 A° c = 8.400 A°
α = 90.00° α = 90.00°
β = 116.04° β = 116.11°
Unit Cell
Parameters
γ = 90.00° γ = 90.00°
Cell Volume Volume = 473 A3 Volume = 474.50 A3
System Monoclinic Monoclinic
Space group P 2 1/C P 2 1/C
3.3.2. Powder XRD Analysis:
The powder form of CS specimen was subjected to PXRD analysis and the recorded
spectrum using Diffraction system XPERT-PRO is depicted in fig.6.[10-11]. The
bragg’s diffraction peaks were indexed and observed prominent peaks confirm the
crystalline nature properties of grown CS crystal
49
Fig:6 shows the Powder XRD for Cesium Sulfamate( JCPS card no: 163835)
3.4. Thermal Analysis:
The thermal stability of Cesium Sulfamate crystals has been recorded using a using a
simulataneous thermal analyzer Q600 SDT and Q20 and DSC instruments. The
amount of the sample for this measurement is 12.4390 mg. The heating rates for the
DSC and TG-DTA measurements were 10 and 20 K/min with flowing dry N2 gas at
40 and 200 ml/min, respectively [12].
Figure.7: shows the DSC and TG-DTA measurements
The TG/DTA and DSC curves of Cs [ NH2SO3] crystal are illustrated in figure. From
the DTA curve, it shows that the melting point of the material takes place in the
50
surrounding area (vicinity) of 227.900C, which indicates there is no phase transition
before this temperature. The sharpness of this endothermic peak shows the high
degree of crystalline and purity of the sample.
0 100 200 300 400 500 600 700 800 900-5
-4
-3
-2
-1
0
Tem
pera
ture
Differ
ence
(0 C)
Temperature(0C)
B
Figure.8. TG/DTA behavior of CS
TG measures the amount and the rate of weight (%) change of a material with
respect to temperature. The TG studies reveals that Cs [ NH2SO3] had gradual
weight loss between 410.02°C up to near 5000C due to the liberation of CO2 and
H2O .The total decomposition of the compound is observed above 800oC. Further it
indicates there is no weight loss below 410.02°C, which shows the material can be
exploited for NLO applications.
0 100 200 300 400 500 600 700 800 900
75
80
85
90
95
100
weigh
t los
s
Temperture
B
Figure.9. TGA studies of CS
In DSC curve, there is a broad exothermic peak at 227.900C to 410.020C, which
corresponds to the decomposition as observed in TG analysis
51
0 100 200 300 400 500 600 700 800 900-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
Hea
t Flo
w
Temperature
B
Figure.10. TG/DSC Curve for Cesium Sulfamate crystal
3.5. Hardness studies:
Vicker’s test
Vicker’s test is said to be a more reliable method of hardness measurement. In order
to get a similar geometrical impression under varying loads, Smith and Sandland
(1923) have suggested that a pyramid be substituted for a ball. The Vickers hardness
test method consists of indenting the test material with a diamond indenter, in the
form of a right pyramid with a square base and an angle of 136° between opposite
faces and subjected to a load of 1 to 100 kg (Figure 8). The base of the Vickers
pyramid is a square and the depth of indentation corresponds to 1/7th of the
indentation diagonal. The longitudinal and transverse diagonals will be in the ratio of
7:1. The full load was normally applied for 10 to 15 s. The two diagonals of the
indentation left in the surface of the material after the removal of the load were
measured using a microscope, and their average was calculated. The area of the
sloping surface of the indentation was calculated. The Vicker’s hardness is the
quotient obtained by dividing the kg load by the square mm area of indentation.[13]
52
Where, HV = Vickers hardness number, P = load in kg, d = arithmetic mean of the
two diagonals. When the mean diagonal of the indentation has been determined, the
Vicker’s hardness number can be calculated from the above formula. Several
different loading settings give practically identical hardness numbers on uniform
material, which is much better than the arbitrary changing of scale with the other
hardness testing methods. The advantages of the Vicker’s hardness test are that
extremely accurate readings can be taken, and just one type of indenter is used for all
types of metals and surface treatments.
Figure-11. Shows the vicker’s Hardness test
Microhardness measurement:
Microhardness studies have been carried out in Cesium Sulfamate single crystals
using HMV Shimadzu microhardness tester filled with diamond Vickers pyramidal
indenter to estimate the mechanical properties. Crystals with flat and smoothness
surfaces were taken for the static indentation test and the same crystal was mounted
on the base of the microscope. The indentations were made gently by varying the
loads from 5 to 25g for a dwell period of 15s using the vicker’s diamond pyramid
indenter attached to an incident ray research microscope. The intended impression of
53
5 10 15 20 2520
30
40
50
60
70
80
90
Hv(
Kg/
mm
2 )
Load(P) Kg
B
vicker’s was approximately square in shape. The shape of the impression is
dependent on the structure, face and materials used.
After unloading, the length of the diagonals was measured by a calibrated
micrometer attached to the eyepiece of the microscope. For each load, at least five
well defined indentations were considered and the average was taken as d. The
elastic stiffness constant (C11) was calculated using Wooster’s empirical relation as
(Wooster, 1953).
The vicker’s hardness was calculated using the standard formula and the values are
tabulated below.
Load (P) Kg Hv (Kg/mm2) C11 x 1014 Pa
5 85.4 23.99
10 67.9 16.06
15 48.8 9.01
20 33.5 4.66
25 25.5 2.89
The values of C11 give the idea of toughness of bonding between neighboring atoms.
Here, the high values of C11 indicates the strong binding forces between the ions,
While the small values of C11 indicates the binding force between the ions are not
quit strong. Thus, the decrease of microhardness with load is in good agreement with
the normal indentation size effect (ISE).[14].
Fig.12 Hardness behavior of Cesium Sulfamate
54
Conclusion:
A high quality semi-organic optical transparent crystal of Cesium sulfamate was
synthesized by slow evaporation solution growth method at a room temperature
using deionised water as a solvent.
1. The crystal parameters, Cell volume, system and space group found to be in
well agreement with that of reported values. At room temperature
Cs(NH2SO3) crystallizes monoclinic with the space group of P21/c .
2. From the Powder X-ray measures, the Bragg’s diffraction peaks were indexed
and observed prominent peaks confirm the crystalline nature properties of
grown CS crystal. The powder XRD confirmed the structure of the crystal
compound.
3. The vibrational frequiencies were assigned from FT-IR spectral analysis,
which confirm the presence of functional groups of the cesium sulfamate
material.
4. The thermal studies confirm that the crystal structure is stable up to 410.020C
and indicate its suitability for use in various applications.
5. The micro hardness study confirms the mechanical strength of the layers of
the sample. Thus, the decrease of microhardness with load is in good
agreement with the normal indentation size effect (ISE).
Reference:
[1] D.S. Chemla and J. Zyss, Academic Press, London (1987).
[2] Marcy H.G,Waarren L.F,Webb M.S,Ebbrs C.A,Velslo S.P,Kennedy G.C, and
Catela G.C,Appl.Opt, 31(1992)5052.
[3] Hou W.B,Jang M.H,Yuan D.R,Xu D,Zhang N,Liu M.G and Tau
mater.Res.bul(1993) 28,645.
[4] Xing G,Jiang M, Zishao X and Xu D J. Lasers 14(1987) 357
[5] Versko S,Laser Program Annual Report, Lawrence UCRC-JC 105000,Lawrence
Livermore National Laboratory Livermore, CA. (1990).
[6] Warren L.F, Electronic Materials our future in: Allred R.E, Martinez R.J,
Wischmann K.B, (Eds), Proceedings of the Foruth International Sample Electronics
55
Society for the Advancement of Materials and Process Engineering Of Materials and
Process Engineering, Covina, (1990)CA,Vol.4 .p. 388.
[7] Landott Bornstein In: K.H.Hettwege, A.M.Hellwege (Eds) ,Numerical Date And
Functional Relationship In Science And Technology,(1982)Group, 14, Springer,
Berlin.p.584.
[8] Sagadevan Suresh, Techniques and tools used for investigating the grown
crystals: A review, (2012).
[9] R. Mohan Kumar, D. Rajan Babu, D.Jayaraman.,R Jayavel and K.Kitamur,
J.Crystal Growth, 275, 1935 (2005).
[10] S. Selvakumar, S.M. Ravi Kumar, Ginson P. Joseph, K. Rajarajan, J.
Madhavan, S.A. Rajasekar, P. Sagayaraj, Materials Chemistry and Physics, (2007)
Vol 103, Issue 1, pp 153-157.
[11] M. Iyanar, J.Thomas Joseph Prakash and S.Ponnusamy, Journal of Physical
sciences, Vol.13,2009,235-244.
[12] J.Chandrasekaran, P.Ilayabarathi and P.Maadeswaran, Rasayan J.Chem, Vol.4,
No.2 (2011), 425-430.
[13] Suresh Sagadevan and R.Varatharajan, international journal of physical
sciences,Vol. 8 (39),PP. 1892-1897, 23 october,2013.
[14] R.Hanumantharao and S.Kalainathan, Bull. Mater. Sci., Vol.36, No.3,June
2013,PP. 471-474, @ Indian Academy of Science.
56
INTRAMOLECULAR WEAK HYDROGEN BONDS IN SOME SIX AND
FIVE ATOM INTERACTIONS: SPECTROSCOPIC ANALYSIS
D.Nandha kumara, Dr.V.Periyanayagasamib
aDepartment of Chemistry, St.joseph’s college of arts and science,
Cuddalore – 607001. bDepartment of Chemistry, St.joseph’s college of arts and science,
Cuddalore – 607001.
Abstract:
CH---X (X = N and O) hydrogen bonds formed intramolecularly in 2-methyl-
4-(2,4,5-trimethoxyphenyl) thiazole (Ia), and 2- amino - 4 - (2,4,5-
trimethoxyphenyl) thiazole (Ib) were studied by means of all-electron calculations
performed with the B3LYP/6-311++G (d,p) method. Computed ground states, in the
gas phase, show the presence of a single H-bond and two H-bonds, CH---N and CH-
--O, for each Ia and Ib molecule. H---N, and H---O distances are shorter than the
sum of the X and H van der Waals radii. H-bond energies of =4.0 kcal/mol were
estimated for Ia and Ib. These results agree with those of the theory of DFT/B3LYP
level, the chemical shifts in the 1H NMR were calculated by the GIAO method; in Ia
and Ib they are merely due to the different topological positions of the H atoms. in
Ia and Ib the shifts of H---N and H---O have signatures of H-bond formations. A
study on the electronic and optical properties (absorption wavelengths, excitation
energy, dipole moment and frontier molecular orbital energies) is performed using
DFT methods. Stability of the molecule arising from hyper conjugative interactions,
charge delocalization has been analysed using natural bond orbital (NBO) analysis.
The calculated HOMO and LUMO energies gap are displayed in the figures, which
show the occurrence of charge transformation within the molecule. NLO properties
related to polarizability and hyperpolarizability are also discussed.
Keywords: Intramolecular hydrogen bonding, Thiazole derivatives, Atomic-ring
interactions, Physical Chemistry, gauge-independent atomic orbital; chemical
shifts;G09 and Veda.
57
Introduction
Thiazole is an important heterocyclic molecule which is strongly
hydrogen bonded in the solid state. and it is a small five membered ring for which
the vibrational spectra have not yet been fully studied computationally[1] Thiazole
and its derivatives have received a great deal of attention and they have versatile
chemistry and constitute reactive moieties of several biochemical systems as well as
ligands of many organometallic compounds[2] There have been several studies
reported for the vibrational analysis of thiazole derivatives in the most of these
studies only the IR spectra with particular emphasis on the N-H and C-H stretching
regions it is anticipated that DFT level of theoretical calculation with two different
basis set are reliable for predicting the vibrational and NMR spectra of 2-methyl-4-
(2,4,5-trimethoxyphenyl)thiazole(Ia).The2-amino-4(2,4,5trimethoxyphenyl)thiazo le
(Ib) has been the object of many spectral, structural and theoretical investigations
because of its interesting chemical and physical properties however the crystal study
of candidate molecule is not available in the literature.
The molecules taken for study are 2-methyl-4-(2,4,5-
trimethoxyphenyl)thiazole and it derivatives. The molecular formula of base
compound is C13H15NO3S and the molecular weight is 265.328g/mol. It is a kind of
beige crystalline powder. Thiazole and phenyl rings in the title molecule with
methoxy substituent is prone to form intramolecular hydrogen bonding, that is
favored both by the free rotation around the C-C bond, joining the thiazole and
phenyl rings and by the kind of hetero atoms or functional groups attached to the
rings. The physicochemical properties of these thiazole derivatives may depend on
the type of H-bonds that these compounds can form. In fact the use of 1H NMR and
X-ray diffraction methods[2,3]. The hydrogen bonding energies were calculated by
rotating about the C-C bond between the rings, breaking the H-bonds, frequency
calculations were done to ensure the structures are minima[7].CH-----X (X= N and O)
hydrogen bonds formed intra molecularly in Ia and Ib. have been studied by means
of all-elecrton calculations performed on B3LYP/6-311++G(d,p) level of theory for
ground state.
58
2.Computational methods
In the present work, DFT hybrid method such as B3LYP/6-311++G(d,
p) method was used to carry out full optimization, which includes relaxation of
geometry and electronic structure of two polysubstituted arylthiazoles derivatives 2-
methyl-4-(2,4,5-trimethoxyphenyl)thiazole (Ia) and 2-amino-4-(2,4,5-
trimethoxyphenyl)thiazole (Ib) was carried out with the B3LYP/6-311++G(d, p)
method. The B3LYP functional has been widely used for the study of weak
hydrogen bonds. All-electron calculations were performed with the aid of the
Gaussian 09 program package on an i7 processor in a personal computer. In DFT
methods, B3LYP is the combination of Beckes three-parameter hybrid function, and
the Lee-Yang-Parr correlation function. The optimized molecular structure of the
molecule obtained using the Gaussian 09 and Gaussview program and is shown in
Fig.1. The observed (FT-IR) and calculated vibrational frequencies and vibrational
assigments are shown in Table 2. Geometric, energetic, topological, and
spectroscopic (chemical shifts) parameters were used for the characterization of
these H-bonds. A vibrational analyses for all molecules were carried out , finding
that the optimized geometries correspond to a minimum on the potential energy
surface, by confirming no imaginary frequencies. Stability of the molecule arising
from hyperconjugative interactions, charge delocalization is analyzed using natural
bond orbital (NBO) analysis. The electronic properties, HOMO-LUMO energies,
Moreover, dipole moment, polarizability, hyper polarizability related to nonlinear
optical (NLO) properties were also studied. The chemical shifts were calculated for
these optimised structures by means of the gauge invariant atomic orbital (GIAO
method).
Results and discussion
3.1. Molecular geometry
In computational study the geometry optimization is the foremost important
step to identify the ground state geometry of candidate molecule. In present study
the geometry of the title molecule has been optimized for B3LYP method with 6-
311G(d,p) basis set along with frequency calculation. Geometry with no imaginary
frequency corresponds to local minima. The optimized geometric parameters of 2-
methyl-4-(2,4,5-trimethoxyphenyl) thiazole derivatives-Ia and 2-amino-4-(2,4,5-
59
trimethoxyphenyl) thiazole derivatives-Ib calculated at DFT theory level [17-19]are
listed in table (1) and they are in accordance with the atomic number scheme given
in Fig (1)
Ia-BondlengthÅ Ib-BondlengthÅ
Figure 1. Optimized B3LYP/6-311++G(d,p) Bond length for the bare Ia-Ib
derivatives. The CH---N, and CH---O distances, in Å, are indicated as well as the
dihedral angles, C5C6C12C13, in deg
Ia-Bond angle Å Ib-Bond angle Å
Figure 2. Optimized B3LYP/6-311++G(d,p) Bond angle for the bare Ia-Ib
derivatives. The CH---N, and CH---O distances, in Å, are indicated as well as the
dihedral angles, C5C6C12C13, in deg
3.2. VIBRATIONAL ANALYSIS
The title molecules are quasi planar with C1 symmetry and there are 33
atoms and 32 atoms in Ia and Ib, respectively there correspond 93 and 92
fundamental vibrations, in fact all are both IR and Raman active. The vibrational
frequencies are further identified interms of PED study using VEDA software. For
60
Thiazole Derivatives The various mode of vibrations computed at DFT/B3LYP6-
311++G(d,p) level have been assigned.
C-H Stretching vibration
The aromatic C-H stretching vibration are normally found in the region
between 3100-2950 cm-1[9-12]. According to the present the aromatic C-H Stretching
vibrations are assigned in the region 3264-3260 cm-1/DFT –B3LYP/6-31G (d,p)
method.
C-C Stretching
The C-C thiazole stretching vibrations give rise to characteristic bands in both
the IR and Raman spectra covering the spectral range from 1600-1400 cm-1[13]
assigned in the region 1664, 1636, 1579 cm-1 DFT/B3LYP-6-31G method. The
phenyl ring C-C Stretching vibration are assigned in the region are 1664, 1636,
1613, 1579, 1558, 1418 cm-1 /DFT/B3LYP6-31G method. This is in good agreement
with literature value[13]
C-N Stretching
The C-N stretching frequency is a rather difficult task since there are problem
in identifying these frequencies from the other vibrations.Silverstein[14-15] assigned
C-N Stretching absorption in the region 1386-1266 cm-1 computed C-N Stretching
vibrations are assigned at 1636, 1299, cm-1 /DFT /B3LYP6-31G method
C-O Stretching
The medium intensity band observed at 1075 cm-1[17] in the IR spectrum could
be assigned to the title molecule has three C-O band their corresponding vibration
are assigned in 1331, 1221, 1182, 1240, 1037 cm-1/DFT /B3LYP6-31G method.
C-H-O-H Out plane Bending vibration
The computed C-H-O-H Out plane Bending vibration are assigned in the
region 1523, 1531, 1506, 1532 cm-1 respectively DFT/B3LYP6-31G method.[14,16]
61
H-C-C-O and H-C-C-N torsional vibration
The computed H-C-C-O and H-C-C-N torsional vibration and C-C-C-S
vibration are assigned in the region 893, 951, 832 and 76, 1522,1088 cm-1
respectively DFT/B3LYP6-31G method.[15]
3.3 Thermodynamic Property
Thermodynamics is the one of the well-developed mathematical descriptions
of chemistry. Computational results can be related to thermodynamics. The results of
computations might be internal energies, free energies and so on, depending on the
computation performed upon the molecule. Likewise, it is possible to compute
various contributions to the entropy[23-25]. Thermodynamic quantities of the title
compound are present in table (5)
Table .5 Theoretical computed energies, zero-point vibrational energies
(kcal/mol), rotational constants, entropies (JK-1) and dipole moment (Debye) for
Thiazole derivatives.
Parameter DFT/B3LYP6-31G
Total energy 175.128
Zero-point energy 684056.9(J/mol)
Rotational constant 0.5954
0.2298
0.1682
Entropy
Total Kcal/mol
Translational 0.889
Rotational 0.889
Vibrational 173.350
62
3.4. NMR STUDY
Theoretical study of the chemical shifts in the 1H NMR was carried outs by
the GIAO method at the B3LYP/6-311++G(d,p) electronic level of treatment[30-36].
This approach also may be useful for a potential identification of H-bonds. The
Calculated chemical shifts, in ppm for some representative hydrogen atoms of the Ia-
Ib Species are shown in Table 10.
Table 10. calculated GIAO B3LYP/6-311++G(d,p) Chemical shifts, in ppm, for
the Benzene H8 and H28 atoms involved in the H-Bond interactions and for the
Aromatic H8 atoms not forming H-Bonds
Molecule H8 H28 H7
Ia 8.49(7.90) 8.23(7.74) 7.54(6.63)
Ib 8.49(7.63) 8.23(7.08) 7.54(6.57)
Some anomalous behavior have been observed for protons of Ia and Ib, specifically,
H8 and H28 which seem to be at the bridging site of phenyl and thiazole rings
moreover they are oriented towards the oxygen of methoxy groups, naturally
susceptible to establish intramolecular H-bonding. This is quite evident from the
large value significantly larger, by 1.42-1.89 ppm, than that of the H7 perhaps, a
signature of blue shift H-bonding. The magnitude of these shifts is in agreement with
the estimated higher H-bond energy, 4.1 kcal/mol for Ia and Ib, which show the
formation of two, C16H28--O29 and C5-H12—N17, H-bonds.[30,32-35]
Conclusion
The non conventional CH---X (X= N, O) H-bonds formed intramolecularly in the
Ia-Ib thiazole derivatives were studied at B3LYP/6-311++G(d,p) level interms of
geometrical and spectroscopic properties to characterize the H-bond centres. The
computed properties for the ground state suggest the formation of an H-bond
between C16H28-O29, in both Ia and Ib which is quite evident from the geometrical
criteria where the H---O distance is found to be 2.241 Å, in both Ia and Ib, however,
63
it is obvious that there is no interaction between C1H7 and N18 which is quite
evident from the bond length H8---N18 2.34-2.35. The chemical shifts in the 1H
NMR were also calculated by the GIAO method to further confirm the blue shift H-
bond signatures from chemical shift values.
REFERENCES
(1) Joule, J. A.; Mills, K. 1,3-Azoles: imidazoles, thiazoles, and oxazoles: reactions and synthesis. In Heterocycle chemistry,4th ed.; Blackwell Sciences Publishing: Oxford, U.K., 2002;pp 402-425. (2) Sa´nchez-Viesca, F.; Berros, M. Heterocycles 2002, 57,1869-1879. (3) Berne´s, S.; Berros, M. I.; Rodrı´guez de Barbarı´n, C.;Sa´nchez-Viesca, F. Acta Crystallogr., Sect. C: Cryst. Struct.Commun. 2002, C58, o151-o153. (4) Castellano, R. K.; Diederich, E. A.; Meyer, E. A. Angew.Chem., Int. Ed. Engl. 2003, 42, 1210-1250. (5) Desiraju, G. R. Acc. Chem. Res. 2002, 35, 565-573. (6) Dincüer, M.; O¬ zdemir, N.; Cü ukurovali, A.; Yilmaz, I. ActaCrystallogr., Sect. C: Cryst. Struct. Commun. 2005, E61,o1712-o1714. (7) Desiraju, G. R.; Steiner The Hydrogen Bond. In The weak hydrogen bond in structural chemistry and biology, 1st ed.; Oxford University Press, Inc.: New York, 1999; pp 1-28. (8) Grabowski, S. J.; Pfitzner, A.; Zabel, M.; Dubis, A. T.;Palusiak, M. J. Phys. Chem. B 2004, 108, 1831-1837. (9) G. Socrates. Infrared and Raman Characteristic Group Frequencies, Tables and Charts, third , John Wiley and Sons. Chichester, 2001 34 C.P. Dwivedi, S.N. Sharma.Indian (10) C.P. Dwivedi; S.N.Sharma; Indian J. Pure appl.Phys. 11(1973) 447 (11) G. Varsanyi. Assignments for Vibrational Spectra of Seven Hundred Benzene Derivatives, 1-2, Addam Hilger, 1974 (12) N.P.Singh; R. A.Yadaw .Indian J.Phys. B75 (2001) 347 (13) N.P.G. Roeges, A Guide to the complete interpretation of Infrared spectra of hetero organic structure, Wiley, New York,1999. (14) M. Silverstein , G.C. Basseler, C.Morill, Spectrometric identification of Organic Compounds, Wiley, New York, 1981. (15) L.J.Bellamy , R.L. Williams, Spectrochem. Acta A9 (1957) 341. (16) N.B. Colthup, L.H.Daly, S.E. Wilberley, introduction to Inftrared and Raman Spectroscopy, Academic Press, New York, 1964. Pp. 226 (17) J.H.S. Green , D.J. Harrison, W.Kynoston, Spectrochim.Acta 27A (1971) 807. (18) ) Becke, A. D. J. Chem. Phys. 1993, 98, 5648-5652. (19) Lee, C.; Yang, W.; Parr, R. G. Phys. ReV. 1988, B37, 785-789. (20) T.Clark, A Hand book of computational Chemistry John Wiley and Sons , New York (1985)(21) A.E.Reed, R.B.Weinstock, F.Weinhold, J.Chem.Phys, 86(1945) PP.735-746.
(22) A.E.Reed, L.A.Curtiss, F.Weinhold, Chem.Rew.88(1988) PP.899
64
(23) Devid C. Young, Computational Chemistry, John Wiley and Sons, New York,
1st ed.,(2001)
(24) W.Cornell, S.Louise-May.Encycl.Comput.Chem.3(1998)PP.1904.
(25) J.J.P.Stewart,Encycle. Comput.Chem.4(1998)PP.241
(26) D.A.Kleinman,Phys Rev.126(1962) PP.1977.
(27) L.J. Bellamy, The Infrared Spectra of Complex Molecules,vol.2,Chapman and
Hall,London,(1982)
(28) R.G.Parr, R.A.Donnelly,M.Levy,W.E.Palke,J.Chem.Phys.68.(1978)PP.3801.
(29) R.P.Iczkowski,J.L.Margrave,J.Am.Chem.Soc.83(1961)PP.3547.
(30) Scheiner, S; Gu, Y.; Kar, T. J. Mol. Struct. (THEOCHEM) 2000, 500, 441-452.
(31) Rozas, I.; Alkorta, I.; Elguero, J. J. Phys. Chem. A 2001, 105, 10462-10467.
(32) Scheiner, S.; Grabowski, S. J.; Kar, T. J. Phys. Chem. A 2001, 105, 10607-
10612.
(33) Mizuno, K.; Ochi, T.; Shindo, Y. J. Chem. Phys. 1998, 109, 9502-9507.
(34) Alkorta, I.; Elguero, J. New J. Chem. 1998, 381-385. CT600336R .Chem. Soc.
1995, 117, 12875-12876.
(35) Ibon Alkorta, Jose Elguero, “Non- conventional Hydrogen Bonds”, Royal
Society of Chemistry, Chemical Society Reviews, vol. 27, no. 2, pp. 163-170, 1998.
(36) George A. Jeffrey, An Introduction to Hydrogen Bonding, Oxford University
Press, New York, USA, 1997, pp. 85, 228.
(37) Gautam R. Desiraju, Thomas Steiner, The Weak Hydrogen Bond, Oxford
University Press, Oxford, UK, 1999.
(38) AIM2000 designed by Friedrich Biegler-konig, University of Applied Sciences,
Bielefeld, Germany,2000.
65
Growth and Characterization of Bis Thiourea Potassium Acid Phthalate
(BTKAP) Single Crystals
N. Jhansi1, K. Mohanraj1, D. Balasubramanian*1
1Raman Research Laboratory, PG & Research Department of Physics, Government
Arts College, Tiruvannamalai-606603
Corresponding author: [email protected] Mobile: +91 9677971999
Abstract
A new non-linear optical single crystal of Bis thiourea Potassium Acid
Pthalate (BTKAP) was grown by slow evaporation technique. The Fourier transform
Infrared Spectrum (FTIR) was recorded for the grown crystal to identify the various
functional groups present in the compound. The X-ray diffraction (XRD) technique
is reported the crystalline nature and crystal structure of the grown BTKAP. The
UV-visible spectral analysis was used to study the linear optical behavior of the
BTKAP single crystals. The second harmonic generation efficiency of the grown
crystal was measured using Kurtz- Perry technique and it is found that two times
more than KDP crystal. It indicates that grown crystal is a potential material for
NLO applications.
Keywords: BTKAP, FTIR, powder XRD, SHG, and UV-Vis.
1. Introduction
In recent trends NLO materials for second harmonic generation (SHG) have
important for an applications in the field of telecommunication, optical computing,
optical information processing, optical data storage technology, laser remote sensing,
laser driven fusion and color displays, in addition to their usual role of extending the
required frequency available from a laser [1-3]. Over the years, many organic and
inorganic materials have been developed to cover the potential applications in
ultraviolet, near and far-infrared wavelength regions [4-6].
Organic crystals with large nonlinear optical (NLO) response make them
suitable for applications in frequency conversion and optical processing [5].Organic
66
nonlinear optical (NLO) materials are often formed by weak Vander Waals and
hydrogen bonds and hence possess a high degree of delocalization. The NLO
properties of organic crystals structure are mainly due to π- bond system. The
overlap of π-orbitals causes the delocalization of electronic charge distribution,
which leads to a high mobility of electrons. This leads to more asymmetry and hence
increased optical nonlinearity.
In the present investigation, potassium acid phthalate has been added to their
in the ratio 1:2 and from the obtained product, single crystal of Bis thiourea
potassium acid phthalate (BTKAP) were grown. The grown crystal was subjected to
various characterization techniques.
2. Experimental procedure
2.1. Material Synthesis
Bis thiourea potassium acid phthalate single crystal was synthesized by using
High purity (99%) Thiourea and Merck grade Potassium Acid Phthalate were taken
in 2:1 molar ratio and dissolved in de-ionized water of resistivity 18.2 MΩ/cm and
stirred with the help of magnetic stirrer for more than four hours at a room
temperature. The prepared solution was taken to dry at room temperature. The Bis
Thiourea Potassium Acid Pthalate (BTKAP) compound was obtained. The purity of
the synthesized compound was improved by successive recrystallization process.
2.2. Seed Preparation
The synthesized BTKAP compound was dissolved in deionized water and the
solution was prepared in slightly undersaturated condition. The solution was
continuously stirred up to 8 hours using magnetic stirrer and then filtered. Then the
filtered solution was transfer to Petri dish and closed by porous paper. The seed
crystals were grown over a period of 10-20 days. Good quality large crystal was
grown from seed crystals by slow evaporation technique. One of the best seeds
obtained was tied hung in the supersaturated solution. After introducing the seed
crystal, BTKAP single crystal was grown to the considerable size as shown in the
figure 2.1
67
Figure 2.1BTKAP single crystals grown from slow evaporation technique.
3. Result and Discussion
3.1. Single crystal X-ray diffraction studies of BTKAP single crystals
BTKAP single crystals was subjected to single crystal X-ray diffraction
analysis using a ENRAF- NONIUS CAD-4 single crystal X-ray diffractometer with
Mo Kα (λ = 0.7170 Å) radiation. The lattice parameter are given in the table 1.the
XRD data of BTKAP crystallize with orthorhombic structure.
Table 1. Single crystal XRD data of TTKAP crystal
Sample Lattice Parameters
a(Å) b(Å) c(Å) V(Å3) BTKAP
6.51 9.77 13.68 90 90 90 887
3.2. Powder X-ray diffraction studies of BTKAP single crystals
The powder sample of BTKAP crystal was subjected to powder X-ray
diffraction analysis using a Rich Seifert diffractometer with CuKα (λ = 1.5418 Å)
radiation. The sample was scanned over the range 10 to 55 degrees at a scan rate of 2
degree/minute. The recorded X-ray pattern of BTKAP is shown in figure 3.2; the
figure shows a sharp and intense peak which confirms the good crystalline nature of
the grown crystal.
Figure 3.2.The powder X-ray diffraction pattern of BTKAP crystal
68
C:\Program Files\OPUS_65\MEAS\BIS.0 BIS Instrument type and / or accessory 07/12/2012
3877
.75
3730
.58
3682
.27
3587
.60
3509
.24
3376
.83
3264
.93
3172
.01
3104
.69
3068
.43
2958
.62
2794
.70
2628
.96
2487
.83
1950
.53
1672
.31
1561
.94
1481
.65
1380
.99
1284
.99
1148
.29
1089
.18
851.
1880
7.54
763.
1971
9.68
681.
1964
5.70
581.
5854
8.32
485.
8142
3.98
391.
27
500100015002000250030003500Wavenumber cm-1
020
4060
8010
0
Tran
smitt
ance
[%]
Page 1/1
3.3. FTIR Analysis
The FT-IR spectrum was recorded using BRUKER IFS-66V FT-IR
spectrometer by pellet technique by KBr pellet technique on the range 400-4000 cm-1
to confirm the presence of the various functional groups in the grown BTKAP
crystals. The infrared spectrum of BTKAP is shown in figure 3.3.
From the FTIR spectrum of the grown crystal, it is found that symmetric C=S
stretching of theory is observed at 719 cm-1. The C-C-O stretching mode occurred at
1089 cm-1. The absorption band at 1561 cm-1 is due to NH2 is group deformation.
The =CH valance and ≡CH valance of there are observed at 3172 cm-1 and 3264
cm-1. The ≡CH symmetrical band is assigned at 3376 cm-1. The peaks at 548 cm-1
shows the C=C-C out of plane ring deformation, 681 cm-1 conforms C-O wagging in
KAP and 854 cm-1 is assigned to C-H out of plane bending is KAP. The absorption
band at 1431 cm-1 and 1672 cm-1 correspond to O-H in plane bending and C≡O
Figure3.3. FTIR Spectrum of BTKAP single crystal
stretching respectively, which conform the presence of functional groups in the
grown BTKAP single crystal.
69
4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 00 .0
0 .5
1 .0
1 .5
2 .0
2 .5
3 .0
3 .5
4 .0
4 .5
Abso
rptio
n (a
.u.)
W a v e le n g th (n m )
3.4 UV- Vis studies
The BTKAP single crystal of thickness 3mm sample was placed in the
Varian Cary 5E UV-VIS-NIR spectrophotometer. The absorption spectrum was
record in the range 200 nm to 1100 nm. The recorded spectrum is shown in the
figure 3.4. The small absorption in the near UV region is due to a weak σ-π*
transitions. As there is no absorption in the entire Vis-NIR range with a lower cutoff
at 330 nm, the transmission window in the visible and IR region so the grown crystal
posses good optical transmission of the second harmonic frequencies of Nd:YAG
lasers[7].
Figure 3.4. Optical Absorption spectrum of BTKAP crystal
3.5. Nonlinear optical studies of BTKAP
The prerequisite for the nonlinear optical crystals is that they should posses
the non-centrosymmetric space group. Hence it is highly desirable to have some
technique of screening crystal structures to determine whether they are non-
centrosymmetric and it is also equally important to know whether they are capable
for phase matching to produce a second harmonic generation.
Kurtz and Perry (1968) [8] proposed a powder SHG method for
comprehensive analysis of the second order nonlinearity (Figure3.5).Kurtz and Perry
second harmonic generation (SHG) test was performed to confirm the NLO property
of BTKAP single crystal. The powdered crystalline sample was illuminated using
Spectra Physics Quanta Ray DHS-2. Need: YAG laser using the first harmonic
output of 1064 NM with pulse width of 8 NS and repetition rate of 10 Hz. KDP
sample was used as the reference material.
70
TEKTRONIX555
EMI 9524PHOTO
MULTIPLIERQ-SWITCHED
LASER1.055 µ
RCA 925PHOTOTUBE
H V SUPPLY
PRE-AMPADYU A-102E
TRIGGER
(w) 2w
CH 1
CH 2
(2w)(w)
Figure 3.5. Schematic diagram of the apparatus used for the study of
second harmonic generation in powder
The second harmonic signal generated in the crystalline sample was
confirmed by the emission of green radiation (λ = 532 nm) from the BTKAP crystal.
The green radiation of 532 nm was collected by a photomultiplier tube (PMT, Philips
Photonics—model 8563) after being monochromatic by a monochromator—model
Triax- 550. The optical signal incident on the PMT was converted into voltage
output at the CRO (Tektronix—TDS 3052B).
A second harmonic signal of 108mv was obtained, while the standard KDP
crystal gave a SHG signal of 46mv/pulse for the same input energy. Hence the SHG
efficiency of the grown crystal is found to be more than two times that of the KDP.
In the powder sample used, the small crystallites were oriented in different directions.
The efficiency of the frequency conversion will vary with the particle size and
the orientation of the crystallites in the capillary tube. Hence, higher efficiencies may
be expected to be achieved with single crystals, by optimizing the phase matching.
4. Conclusion
The Bis thiourea potassium acid phthalate was synthesized and the seed
crystals were grown from the crystallization by slow evaporation technique. The
Purity of the synthesized crystals was improved by successive recrystallization
process. The X-ray diffraction analysis confirmed the crystalline nature and
structure of the grown BTKAP single crystal. The FTIR spectrum was confirm the
presence of the various functional groups in the grown crystal. UV visible spectrum
of grown crystal as the lower cut off value 330nm; it is a potential material for NLO
71
applications. Kurtz- Perry powder technique confirmed the NLO property of the
grown BTKAP crystal and its second harmonic generation efficiency is found to be
more than 2 times that of KDP.
References
[1] Yuan D., Zhong Z., Liu M., Xu D., Qi Fang, Bing Y., Sun S. and Jiang M.
(1998), ‘Growth of cadmium mercury thiocynate single crystal for laser diode
frequency doubling’, J. Crystal Growth, Vol. 186, pp. 240-244.
[2] Anandhabahu G., Bhagavanarayana G., Ramasamy P., (2008), Journal of
crystal growth 310(2008)2820-2826.
[3] Prasad P. N., Williams D. J., (1991) Introduction to Nonlinear Optical Effects
in Molecules and Polymers, Wiley- Interscience, New York.
[4] Hann R.A. and Bloor D. (1989), ‘Organic Materials for Nonlinear Optics’, the
Royal Society of Chemistry, Special Publications No. 69.
[5] Badan J., Hierle R., Perigaud A. & Zyss J. (1993) NLO Properties of
Organic Molecules and Polymeric Materials, American Chemical Society
Symposium Series 233; American Chemical Society: Washington, DC.
[6] Chemla D.S. and Zyss J. (1987), ‘Nonlinear optical properties of organic
molecules and crystals’, Academic Press, Orlando, New York, Vol. 1-2.
[7] Kannan V., Rajesh N.P., Bairava Ganesh R., Ramasamy P. ‘Growth and
characterization of Bisthiourea- Zinc Acetate, a new nonlinear optical
materials’ , Journal of Crystal Growth 269(2004) 565-569.
[8] Kurtz S.K. and Perry T.T. (1968), ‘A Powder technique for the evaluation of
nonlinear optical materials’, J. Appl. Phys., Vol. 39, pp. 3798-38l3.
72
Growth, Structural, Thermal, and Mechanical Properties of Succinic Acid
Doped Potassium Hydrogen Phthalate (KHPSA) Crystal
R. Aruljothia, R. U. Mullaia, E. Vinotha, M. Sheik Muthalia, S. Vetrivela*
aPG & Research Department of Physics, Government Arts College, Tiruvannamalai-
606 603, India
*Corresponding author: [email protected]
Abstract
Succinic acid doped Potassium hydrogen phthalate (KHPSA) semi-organic
single crystals were grown by slow evaporation method at room temperature. Single
crystal X-ray diffraction study revealed that the KHPSA crystal belongs to
orthorhombic system. FTIR spectral analysis confirms the presented functional
groups in the synthesized compound. The UV–Vis–NIR spectrum showed that the
grown crystal is transparent in the entire visible region. The hardness profile of the
sample is investigated by Vicker’s micro hardness test. TGA/DTA analysis were
carried out to characterize the melting behavior and stability of the title compound.
Microstructure and compositions of the KHPSA crystal was carried out by SEM with
EDS.
Keywords: crystal growth, X-ray diffraction, FTIR spectral analysis, UV–Vis–NIR
spectrum, micro hardness, thermal analysis, and SEM.
1. Introduction
The search for new conversion materials for various device applications has
led to the discovery of many organic, inorganic and semi organic Non Linear Optical
(NLO) materials. Among these, Semi organic crystals have attracted considerable
interest due to their large NLO coefficients, high resistance to laser induced damage,
low angular sensitivity, excellent mechanical hardness fluorescence properties
because of their potential applications such as, telecommunication, optical
computing, optical data storage, light emitting diodes, and optical information
processing [1, 2]. Semi organic compounds exhibits dipolar structure, improved
mechanical-thermal properties, chemical stabilities and bulk crystal morphologies.
Potassium hydrogen phthalate (KHP) is also called as potassium acid
phthalate (KAP) is a semi-organic material. It is also one of the important NLO
73
crystals in the alkali metal acid phthalate (MAP) family [3]. It belongs to the
orthorhombic class of alkali acid phthalate series. The crystal structure of KAP is
assigned to the Pca21 [4] space group, consisting of potassium ions and alkali
phthalate ions. Recently KAP crystals were used as substrate for epitaxial growth of
oriented polymers [5, 6] and for hierarchical growth of organized materials [7]. KAP
crystals are playing an important role in the field of NLO materials, they are known
second harmonic generating materials that have long stability in devices due to their
electro- optical properties [8] and exhibit interesting piezoelectric, pyroelectric and
elastic properties that are useful in many application [9,10]. Its higher chemical
stability and economic viability with good kinetic growth properties have made to
pay attention on it in past decades.
Generally Succinic acid has wide applications in many fields, like industry,
medicinal, organic intermediates for the pharmaceutical, engineering plastics, resins.
Particularly in the chemical industry it is used for the production of dyes, alkyd resin,
glass fiber reinforced plastics, ion exchange resins and pesticides.
By using these potential sites, in the present work, the effect of succinic acid
on thermal, optical, mechanical properties of KHP have been analyzed. The grown
crystals were subjected to different characterization such as single crystal XRD,
Powder XRD, UV-visible absorption study, FTIR spectral studies, Micro hardness,
and SEM.
2. Experimental
2.1. Synthesis and Growth
The KHPSA salt was obtained from an aqueous solution containing potassium
hydrogen phthalate and succinic acid in a 1:1 molar ratio. The calculated amount of
starting materials for the synthesis was obtained according to the reaction.
K(C6H4COOH-COO)+C4H6O4 KC8H5O4. C4H6O4
The calculated amount of KHP was first dissolved in Millipore water of 18.2
MΩ cm resistivity. The calculated amount of succinic acid added to the solution
slowly and stirred well using a temperature controlled magnetic stirrer about 18
hours to yield a homogenous mixture of solution. Then it was double times filtered
with Wattmann filter paper and poured into petri dishes. Then the filtered solution
74
was allowed to evaporate at room temperature and the mixed salt was obtained by
slow evaporation technique. The purity of the synthesized salt was further improved
by successive recrystallization process. By this method the seed obtained has been
used for the bulk growth. A good quality single crystal with size 13 × 5 ×2 mm3 was
harvested at the period of 23 days with appropriate growth rate of 0.56 mm/day. The
photograph of as grown KHPSA crystal is shown in figure 1.
Fig 1. Grown KHPSA Crystals
3. Result and Discussion
3.1 Single Crystal X-ray Diffraction Studies
The grown KHPSA crystals were studied intensively since they started to be
used as X-ray monochromator and X-ray analyzers. A fine quality KHPSA crystal
was kept on an Xcalibur, Eos diffractometer at 293(2) K. Single crystals X-ray
diffraction analyses of this single crystal have been carried out and the unit cell
parameter values are given in the table 1.
Table 1. Comparison of Unit Cell Parameter Values of KHPSA, Pure KHP and
Succinic Acid
Crystal a(Å) b(Å) c(Å) V(Å3) Crystal
system
Space
group
KHPSA 5.54 7.71 8.6 367 Orthorhombic P
Pure
KHP 6.46 9.57 13.28 828.831 Orthorhombic P21
SA acid 7.0511 9.7836 4.6868 341.62 Triclinic P21
75
From the result it has been found that the unit cell parameters of KHPSA are
decreased with respect to pure KHP, as shown in Table 1. The change in unit cell
volume of KHPSA with respect to pure KHP confirmed that the doping of succinic
acid into KHP crystal. From the unit cell parameter values, the dependence of the
lattice parameter ‘b’ and the corresponding volume change, clearly reveal that the
crystal undergoes non-uniform strain due to the presence of dopant.
3.2 Powder X-ray Diffraction
Powder X-ray pattern for NLO single crystal was recorded and shown in
figure 2. To identify the reflection planes and to check the crystalline perfection of
the grown crystal, powder X-ray diffraction patterns of the powdered sample have
been recorded using a Reich Seifert diffractometer with CuKα (λ = 1.5418 Ǻ)
radiation at 30 kV, 40 mA. The synthesized grown crystal was scanned over the
range from 10° to 80° diffraction angle at a scan rate of 2 % minute at room
temperature.
0 10 20 30 40 50 60 70 80 90
0
5000
10000
15000
20000
25000
Inte
nsity
(a.u
)
2 Theta(deg)
Fig 2. Powder X-ray Diffraction Pattern of KHPSA Crystal
The indexed pattern of KHPSA crystal consists a set of prominent sharp peaks
as shown in figure 2. The well-defined peaks at specific 2-theta values show high
crystalline of the grown crystal.
76
3.3 FT-IR Spectral Studies
The FTIR is used to identify the different functional groups present in the
compound of the grown crystal. The FTIR spectrum of KHPSA crystal was recorded
in the region 500–4000 cm-1 from KBr pellets on a Perkin Elmer FTIR
spectrometer as shown in figure 3.
Fig 3. FT-IR Spectrum of KHPSA Crystal
The band 2885cm-1 has been assigned to the C-H stretch. The 2648 cm-1 is
characteristic of C-H stretch. The other peak at 2522 cm-1 is assigned to O-H
bending. The peak at 1949 cm-1 represents C=C asymmetric stretch. The peak at1680
cm-1 represents -C=C- stretching. The peak at 1579 cm-1 is assigned to N-H bending.
The peak at 1398 cm-1 is assigned to C-C stretching. The very strong peak observed
at 1279 cm-1 is attributed vibration of the C-H Wag. The peak at 1071 cm-1 is
assigned to C-N stretching. The predominant peaks appeared between 903 and 553
cm-1 may be due to the vibrations involved by metal atoms in the crystal [11].
3.4 Optical Absorption Spectra
The optical absorbtion spectrum of the grown KHPSA was recorded using
Perkin Elmer Lambda 35 UV-Visible spectrophotometer in the wavelength range
from 200 to 900 nm. The recorded spectrum is shown in figure 4. The KHPSA
crystal has the lower cut-off wavelength at 210 nm in the UV region. The crystal
77
does not exhibit any absorption band in the entire visible region up to 850 nm. The
spectrum exhibits the strong absorption peak at 210nm. The absorption peak at 210
nm is assigned to π and π* transition of the compound. Absence of absorption
between 220 nm and 870 nm is an advantage, as it is the key requirement for
materials possessing SHG properties. As a result, it can be used as a potential
candidate for the SHG device applications in the visible region [12].
Fig 4. UV-Vis Absorption Spectra of KHPSA Crystal
3.5 Thermal Analysis
In order to study the thermal stability of the grown crystals, thermo
gravimetric (TG) and differential thermal analysis (DTA) have been carried out
using a Seiko TG-DTA 6200 model thermal analyzer in an inert nitrogen
atmosphere. Powdered sample of about 3.374 mg was used for the analysis in the
temperature range of 30 - 500°C with a heating rate of 20°C/minute. The TG-DTA
pattern recorded for the KHPSA crystal as shown in figure 5.
78
Fig 5. TG-DTA Curves of KHPSA Crystal
The above TG curve major weight loss occur at three stages. First weight loss
occur with 88.44% at 94 °C. The second weight loss occurs with 43.50% at 65°C
and the third weight loss occur with 38.41% at 52 °C. The weight losses are
conformed for sharp endothermic peaks of a DGTA trace. The three endothermic
peaks occurring at different temperatures. These three different stages indicate the
decomposition of the substance. This indicates that the crystal have high melting
point (188.82 °C) and it exhibit high thermal stability.
3.6 Micro hardness Test
The micro hardness testing is a characterization technique that can be well
suited to study the mechanical properties of the material, such as fracture behavior,
yield strength, brittleness index and temperature of cracking [13].
The indenter load ‘P’ is related with micro hardness number ‘Hv’by using the
relation
Hv = 1.8544 (P/d2) kg/mm2 --------------------- (3.1)
Where ‘d’ is the mean diagonal length of the impression in mm. The relation
between ‘Hv’ and ‘P’ for the grown crystals has been shown in figure 6.
79
1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50-2.1
-2.0
-1.9
-1.8
-1.7
-1.6
-1.5
-1.4
-1.3
-1.2
Log
P
Log d
Fig 6. Variation of Hardness Hv with load P for KHPSA Crystal
The Mayer’s index number or work-hardening coefficient ‘n’ was calculated
from the Mayer’s law [14], which relates the load (P) and indentation diagonal
length (d). P = kdn ------------------- (3.2)
where ‘k’ is the material constant. To estimate the work hardening coefficient
‘n’, for KHPSA crystal. Graph is drawn between log ‘d’ and log ‘P’ as shown in
figure 7.
Fig 7. Variation of log ‘d’ against log ‘p’ for KHPSA Crystal
The slope of the curves, after least square fitting, gives the value of ‘n’. The
‘n’ value of KHPSA crystal were found to be 2.06. The value is more than 1.6 it is
concluded that the crystals belong to soft category material [15].
80
3.7 SEM with EDS Analysis
SEM analysis provided information about the nature, suitability for device
fabrication and also it is used to check the presence of imperfections. SEM analysis
was carried out using JEOL JSM-5610 LV scanning electron microscope with an
accelerating voltage of 20 KV, at high vacuum mode and secondary electron image
(SEI). Since semi organic crystals are non-conducting in nature, gold coating (JEOL
auto fine Coater JFS-1600) was done for 120 s before subjecting KHPSA crystal
surface to electron beam [16]. KHPSA crystal has well developed morphology with
several habit faces (Figure 8). It exhibiting layered growth and it is observed that the
basic units are arranged in different layers, which is a clear evidence for the stacking
of fundamental units during crystal growth. KHPSA crystal was also analysed by
energy dispersive spectroscopy (EDS) for qualitative and quantitative information
and shown in figure 9. From the EDS spectra potassium (k) metal present in the
KHPSA crystal.
Fig 9. EDS Spectrum of KHPSA Crystal
4. Conclusion
Good quality single crystals of the succinic acid doped KHP crystal were
grown by slow evaporation solution growth technique. Lattice parameters were
calculated from the XRD characterization to compare with pure KHP and succinic
acid. Powder XRD studies reveals thatthe grown KHPSA crystal is having good
crystallinity. The optical transmission spectrum showed that succinic acid doped
KHP crystal has good transparency in the UV-Vis. The FTIR spectrum reveals the
81
various functional groups present in the grown crystal. The TG/DTA analysis shows
that the thermal stability of the grown KHPSA crystal. Vicker's micro hardness
studies were determined the KHPSA crystal found to be soft material category. The
surface morphology and some elemental compositions of the crystal were reported
by SEM with EDS analysis.
References
1. Wiliams, J., 1983. American Chemical Society Symposium Series 233,
American Chemical Society. Washington. DC.
2. Chemla, DS., Zyss, J., 1987. vol (1-2), Academic press, New York.
3. Kumaresan, P., Moorthy Babu, S., Anbarasan, PM., 2008. Optical Materials.
30, 1361-1368.
4. Okaya, Y., 1965. Acta Crystallogr. 19, 879.
5. Timpanaro, S., Sassella, A., Borghesi, A., Porzio, W., Fontaine, P.,
Goldmann, M., 2001. Adv. Mater. 13, 127.
6. Haber, T., Resel, R., Thierry, A., Campione, M., Sassela, A., Moret, M.,
2008. Physica E41, 133.
7. Oaki, Y., Imai, H., 2005. Chem. Commun. 48, 6011.
8. Kejalakshmy, N., Srinivasan, K., 2003. J. Phys. D, Appl. Phys. 36, 177.
9. Miniewicz, A., Bartkiewicz, S., 1993. Adv. Mater. opt. EWlectron. 2, 157.
10. Kejalakshmy, N., Srinivasan, K., 2004. Opt. Mater. 27, 389.
11. Petrosyan, AM., Sukiasyan, RP., Karapetyan, HA., Terzyan, SS., Feigelson,
RSJ., 2000. Crystal Growth, 213, 103.
12. Kirubavathi, K., Selvaraju, K., Vijayan, N., Kumararaman, S., 2008.
Spectrochim. Acta A, 71, 288.
13. Sharda, J., Shitole and Saraf, K., 2001. B Bull. Mater Sci., 24, 461-468.
14. Chacko, E., Mary Linet, J., Mary Navis, S., Priya, C., Vesta, B. 2006. Milton
Boaz, S. Jerome Das, Indian. J. Pure Appl. Phys, 44, 260.
15. Gong, J., 2000. Mater. Sci. Lett, 19, 515.
16. Jerald Vijay, R., Melikechi, N., Rajeshkumar, T., Jesudurai, M., Sagayaraj, P.,
2010. J. Cryst Growth. 420-425
82
GROWTH AND IN-VITRO STUDIES ON CYSTINE URINARY STONE IN
SILICA GEL MEDIUM
M.Saravana Kumar1* and F.Liakath Ali Khan2 1Department of Physics, Muthurangam Govt. Arts College, Vellore, Tamilnadu,
India. 2Department of Physics, Islamiah College, Vaniyambadi, Tamilnadu, India.
Abstract
Cystine is found rarely (about 1%) in urinary stones. These crystals were
grown by the single diffusion gel growth technique in sodium metasilicate gel.
The crystals were found to be having single, twinned and bunched hexagonals,
cubic, rectangular, bipyramidal and needles morphologies were obtained.
Crystal of hexagonal morphology, structure and elemental composition of the
grown crystals have been analyzed using SEM -EDAX and powder XRD
studies. Functional groups present in the grown crystals have been confirmed
from the FTIR spectrum. This was in agreement with earlier reported studies.
Key words: Urinary stones, Cystine crystal, growth parameters, Powder XRD, FTIR,
surface morphology ,EDAX and thermal studies.
1. INTRODUCTION
The pathological mineralization may be defined as crystal deposition diseased
associated with the presence of microcrystals which contribute to tissue damage and
cause pain and suffering. Significance of the in vitro investigation of the urinary
stone mineralization on human body was employed by Nancollas et al., 1992.
Kidney stones developed by various metabolic and environmental-nutritional
factors including hypercalciuria, hyperoxaluria, hyperuricosuria, hypercitraturia,
under urinary acidity, cystinuria and low urine volume. For the treatment of
urolithiasis, there are different drugs are used such as thiazide diuretics, potassium
citrate, low calcium diet for hypercalciuria, allopurinol for hyperuricosuria,
magnesium citrate for hyperoxaluria, chelating agents for cystinuria and antibiotics
for infection stones. (Pak CYC et al 1976).
83
2. MATERIALS AND METHOD
A gel is defined as a two component system of a semi-solid in nature, rich in
liquid. It is also termed as loosely inter-linked polymer. Importances of gel medium
are as follows
Crystal can be grown in room temperature. Hence it will have lower concentration of
non- equilibrium defects, than those grown at elevated temperature. Crystal can be
observed practically in all stages of growth. It forms three dimensional structure
entrapping water. It remains chemically inert, prevents turbulence. Rate of reaction is
controlled. Concentration of reactants can be easily varied. Crystals of different
morphologies and sizes can be obtained by changing the growth condition. The
grown crystal can be easily harvested, without damaging the crystal face. This
method is extremely simple and inexpensive. Silica gel is the best and most versatile
growth media (Henisch, 1988).
A stock solution of sodium meta silicate is prepared by adding 100ml of
distilled water to 60 grams of sodium meta silcate powder (Na2SiO3.9H2O). Using
this solution one can prepare gels of various specific gravity. Very dense gels
produce poor crystals and gels of insufficient density take a long time to form crystal
and are mechanically unstable. A specific gravity of 1.04g/cm3 appears to be the
ideal value to grow cystine crystals.
3. GROWTH OF CYSTINE CRYSTALS
Cystine crystals were grown by gel method (Girija et al., 1995). Solution was
prepared by dissolving a small amount of L-Cystine in sodium meta silicate of
specific gravity 1.04 g/cc and then pH was adjusted to 6.0 by treating it with glacial
acetic acid and the solution was allowed to set. Crystals of cystine having different
morphologies viz., single, twinned and bunched hexagonals, cubic, rectangular,
bipyramidal and needles were obtained.
84
Fig.1. As grown crystal Fig.2. Harvested crystal
4. Results and discussion
4.1.Powder XRD analysis
The powder X-ray diffraction pattern of hexagonal shaped crystal is shown
in Fig. 3. The d values obtained from the reflections of harvested crystal agree well
with that of cystine (JCPDS, PDF No. 23-1663). The cystine crystals belong to
hexagonal system with space lattice P6122. Lattice parameters, a = 5.436 Å and c
= 56.37Å (Goldfarb et al., 2006).The powder XRD patterns of gel grown urinary
crystals is shown in figure 3.
4.2 FTIR spectrum of Cystine crystal
FTIR spectrum is recorded IR spectrum of cystine (Figure 4) using KBr pellet
method. The absorption band at 3026 cm-1 has been assigned to CH stretching
vibrations. The two bands at 1622 and 1584 cm-1 are assigned to NH, deformation.
The band observed at 1408 cm-1 is related to the mixed vibrational modes of C-H
bending and COO- stretching modes. The bands at 1382 cm-1 and 1337 cm-1 has
been assigned to C-H bending and C-C stretching, respectively. C-S stretching
vibration is seen at 675 and 615 cm-1. The sharp band at 540 cm-1 is attributed to the
S-S stretching mode. This is in well agreement with the result of Girija et al., 1995.
85
Fig.3. Powder XRD of Cystine crystal Fig.4. FTIR spectrum of Cystine crystal
Fig.6. SEM Picture of Cystine crystal Fig.7. EDX Pattern of Cystine crystal
4.3 SEM and EDX studies
Figure 5 & 6 represent the SEM and EDAX analysis of gel grown
Cystine crystal. From this one may conclude that cystine crystals exhibits hexagonal
surface morphology and the elemental composition of the grown crystal were
identified by EDAX analysis. The Energy Dispersive X-ray Spectroscopy (EDX)
86
analysis of cystine crystal revealed the presence of 42.857% of Carbon atoms
along with expected Oxygen (28.571%), nitrogen and sulphur (14.286%).
5. CONCLUSION
Cystine crystals have been grown in SMS gel. Growth parameters are
standardized. Powder XRD analysis confirm the crystal nature of the gel grown
crystal and the lattice parameters have been determined. FTIR studies reveal the
presence of various functional groups. Surface morphology and compositional
details are studied using SEM and EDX studies.
References
1. Heinz. K. Henisch, “ Crystals in Gels and Liesegang Rings”, Cambridge
University press, (1988).
2. George H. Nancollas, The involvement of calcium phosphates in biological
mineralization and demineralization processes , Pure & Appl. Chern., 64(11),
1673-1678, (1992).
3. Girija. E.K, Narayana Kalkura. S and Ramasamy.P, Crystallization of cystine,
Journal of Materials Science: Materials in Medicine, 6, 617-619, (1995).
4. Goldfarb D. S., Coe F. L. and Asplin J. R., Urinary cystine excretion and capacity
in patients with cystinuria. Kidney Int., 69, 1041-1047, (2006).
5. Pak, C. Y. C, Hayashi. Y and Arnold, L. H, Heterogenous nucleation between
urate, calcium phosphate and calcium oxalate, Proceedings of the Society of
Experimental Biology and Medicine, 153, 83–87, (1976).
87
CHARACTERIZATION AND THEORETICAL PROPERTIES OF DIHYDROXY COUMARIN, NLO SINGLE CRYSTAL BY DFT METHOD
K.Sambathkumara* , R.saradhaa, A.Claudea and K.Settua.
aP.G.&Research Department of Physics, A.A.Govt.Arts College, Villupuram-605602
ABSTRACT Dihydroxy coumarin (DHC), a semi-organic nonlinear optical material, has been
synthesized and single crystals were grown from ethanol solution at room
temperature up to dimensions of 4.7cm×4.1cm×3cm. The unit cell parameters were
determined from single crystal and powder X-ray diffraction studies. The structural
perfection of the grown crystal has been analyzed by X-ray diffraction (XRD) study.
The variation of dielectric properties of the grown crystal with respect to frequency
has been investigated at different temperatures. Microhardness measurements
revealed the mechanical strength of grown crystal. The optical parameters, the
optical band gap Eg and width of localized states Eu were determined using the
transmittance data in the spectral range 200–800 nm. The relative second harmonic
efficiency of the compound is found to be 1.4 times greater than that of KDP and
ADP. Static deformation, dynamic deformation & Laplacian map are also
constructed. And the theoretical studies were conducted on the molecular structure
and vibrational spectra of vinyl benzoate (DHC). The FT-IR and FT-Raman spectra
of DHC were recorded in the solid phase. The molecular geometry and vibrational
frequencies of DHC in the ground state have been calculated by using the density
functional methods (B3LYP) invoking 6-311++G(d,p) and 6-311+G(d,p) basis set.
The optimized geometric bond lengths and bond angles obtained by DFT method
show best agreement with the experimental values. A detailed interpretation of the
FT-IR and FT- Raman, spectra of DHC was also reported. Such as HOMO and
LUMO energies, were performed by time dependent density functional theory (TD-
DFT) approach. Finally the calculations results were applied to simulated infrared
and Raman spectra of the title compound which show good agreement with observed
spectra.
Keywords: FTIR, FT-Raman, HOMO- LUMO, MEP, DHC. *Corresponding author. E-mail address: [email protected](K.Sambathkumar)
88
Introduction The dimer of dihydroxy coumarin moiety (Figure 1) is a common fused
heterocyclic nucleus found in many natural products of medicinal importance.
Several of these natural products exhibit exceptional biological and pharmacological
activities such as antibiotic, antiviral, anti-HIV, anticoagulant and cytotoxicity
properties. Additionally, coumarin derivatives have been used as food additives,
perfumes, cosmetics, dyes and herbicides. Recently, Supuran et al. reported that
coumarin derivatives constituted a totally new class of inhibitors of the zinc
metalloenzyme carbonic anhydrase. Additionally, two new series of dihydroxy
coumarin analogues have been synthesized as inhibitors of the enzyme of human
NAD(P)H quinine oxidoreductase-1 (NQO1), which is expressed in several types of
tumor cells[1]. A series of coumarins bearing different groups on the aromatic ring
were synthesized and tested as caspase activators and apoptosis inducers, showing
that these compounds can be used to induce cell death in a variety of conditions in
which uncontrolled growth and spread of abnormal cells occurs. Moreover, coumarin
dyes have attracted much interest owing to their application in organic light-emitting
diodes (OLEDs). As a result of showing a wide range of size, shape and
hydrophobicity, coumarins are used as sensitive fluorescent probes of systems
including homogeneous solvents and mixtures and heterogeneous materials. In
addition, they form host-guest inclusion complexes with cage-like molecules such as
cyclodextrins and cucurbiturils . The interest in the biological activity of dihydroxy
coumarin continues nowadays, with warfarin and acenocoumarol being two of these
derivatives which have been marketed as drugs. Warfarin has been the mainstay of
anticoagulation therapy worldwide for over 20 years, therefore a series of similar
derivatives have been synthesized and tested as anticoagulant agents.
Acenocoumarol acts in the same way, therefore several dihydroxy coumarin
derivatives have been synthesized and their pharmacological activity was tested[2].
Results and Discussion
As part of our program studying the chemistry of fused heterocyclic systems
with specific functional groups we wish to report herein an extended methodology
for the synthesis of3-functionalized-dihydroxy coumarin, applying as alternative and
89
ultimate scaffold, the N-hydroxysuccinimide ester of O-acetylsalicylic acid, for the
“coupling reaction” with an active
methylene compound. The chemistry proceeds via a tandem intermolecular
nucleophilic coupling of the N-hydroxysuccinimide ester of O-acetylsalicylic acid
with an active methylene compound, and the subsequent intramolecular cyclization
of the intermediate to a stable six-membered ring system, the coumarin nucleus, as
shown in Fig 1.This approach would provide an alternative general method for the
synthesis of coumarins and other similar organic molecules containing the
benzopyranone ring system. The proposed protocol involves the following steps: a)
the deprotonation of an active methylene compound; b) the nucleophilic attack at the
carbonyl of the N-hydroxysuccinimide ester; c) the in situ intramolecular cyclization
of the “intermediate” precursor affording the functionalized heterocycles bearing the
coumarin nucleus. The key control element of this approach is the utilization of the
N-hydroxy-succinimide ester of O-acetylsalicylic acid. This acylating agent was
synthesized by condensation of equimolar amounts of O-acetyl-protected salicylic
acid and N-hydroxy succinimide (NHS) in the presence of 1.2 equiv. of dicyclo
hexylcarbodiimide (DCC) in anhydrous tetrahydrofuran at 0 °C. This excellent
activating synthon was isolated in good yields as a white solid and was used in the
next step without further purification. The C-acylation protocol involved the reaction
of 2 equiv. of an active methylene compound with 2 equiv. of sodium hydride in
anhydrous tetrahydrofuran at0 °C. After 1 hour of continuous stirring, 1 equiv. of the
N-hydroxysuccinimide ester was added and the mixture was stirred for 2 hours, at
room temperature. In consequence, the solvent was removed under reduced pressure,
the gummy solid was diluted with water, washed with diethyl ether and the aqueous
layer was acidified with aq. solution of hydrochloric acid 10%, to give after
extraction with dichloromethane, the intermediates as oily products. Cyclization of
these C-acylation compounds was affected by refluxing them with two-fold excess
amount of sodium ethoxide in ethanol for 24 h or by mixing them with aq. solution
of hydrochloric acid 10% in methanol for 48 h at room temperature. Several features
of the proposed methodology make it synthetically useful: the starting materials are
inexpensive and stable; the yields are good; the reactions are relatively rapid and
90
proceed at ambient temperature or under mild and easily controlled conditions.
Furthermore, the methodology can be expanded to other heterocyclic systems
bearing different heteroatoms or functions on the heterocyclic and/or aromatic ring.
X-ray Crystallographic Analysis
The crystal of this compound belongs to the monocyclic space group P2(1)/c. The
data were collected at 150(2) K on a Bruker Apex II CCD diffractometer using
MoKα radiation (λ = 0.71073 Å). The structure was solved by direct methods and
refined on F2 using all the reflections. Parameters for data collection and refinement
are summarized in Table 1. Crystallographic data of dihydroxy coumarin and
selected bond lengths and angles are given in Table 2. The crystal structure and
packing diagram of this compound are given in Figures 2 and 3 respectively. The
structure resembles with a double bond character in C(8)-C(9) (1.37 Å) and the bond
C(8)-O(3) distinctly longer than the conventional carbonyl distance for C(1)-O(1)
(1.31 Å and 1.19 Å respectively)[2]. The molecules show π-π stacking principally
with a planar distance of 3.9 Å.
HOMO–LUMO energy gap and related molecular properties
The interaction of two atomic (or) molecular orbitals produces two new
orbital. One of the new orbitals is higher in energy than the original ones (the anti
bonding orbital) and one is lower (the bonding orbital). When one of the initial
orbitals is filled with a pair of electrons (a Lewis base) and the other is empty (a
Lewis acid), we can place the two electrons into the lower, energy of the two new
orbitals. The "filled-empty" interaction therefore is stabilizing. When we are dealing
with interacting molecular orbitals, the two that interact are generally the highest
energy occupied molecular orbital (HOMO) and lowest unoccupied molecular
orbital (LUMO) of the compound. These orbitals are the pair of orbitals in the
compound, which allows them to interact most strongly. These orbitals are
sometimes called the frontier orbitals, because they lie at the outermost boundaries
of the electrons of compound. The HOMO-LUMO analysis for the title compound
has been carried out using B3LYP/6-311++G(d,p) method. The computed values of
HOMO and LUMO are tabulated in Table 3. From the table shows that energy gap
91
explains the eventual charge transfer within the molecule. The HOMO-LUMO plots
are shown in Fig 4. In this investigation, the more relevant electronic potential (IP),
electron affinities (EA), chemical potential (µ) it is the negative of electro negativity
(χ), hardness (η), softness (S), electrophilic index(ω) and the electric dipole
polarizability (α) were calculated. The ionization potential is calculated as the energy
difference between the energy of the molecule derived from electron-transfer (radical
cation) and the respective neutral molecule; IP = Ecation - En. The EA was
computed as the energy difference between the neutral molecule and the anion
molecule: EA = En+ Eanion . The HOMO and LUMO energy was also used to
estimate the IP and EA in the framework of Koopmans’ theorem:
IP = -εHOMO and EA= - εLUMO
Within the framework of the density functional theory (DFT), one of the global
quantities is chemical potential (µ), which is measures the escaping tendency of an
electronic cloud, and equals the slope of the Energy versus N(number of electrons)
curve at external potential ν(r)[3] :
µ = (E/N)V(r)
Finite difference approximation to Chemical Potential gives,
= -µ = -(E/N)V(r)
The theoretical definition of chemical hardness has been provided by the density
functional theory as the second derivative of electronic energy with respect to the
number of electrons N, for a constant external potential ν(r)[4] :
η = ½(2E/N2)V(r) = ½( µ/N)V(r)
Finite difference approximation to Chemical hardness gives,
η = ( I-A )/2
For Insulator and semiconductor, hardness is half of the energy gap (εHOMO - εLUMO ),
and the
softness is given as :
S = 1/2η=(2E/N2)V(r)= (E/N)V(r)
92
Electrophilicity index is a measure of energy lowering due to maximal electron flow
between donor and acceptor. Electrophilicity index (ω) is defined as,
= µ2/2 η
B3LYP functional used in this study has a high efficient to calculate the electronic
properties for the organic studied molecules, such as ionization potentials (IP),
electron affinities (EA), electro
negativity (χ), absolute hardness (η), absolute softness (S), electrophilic index
(ω)[3]. The first one being energy-vertical is based on the differences of total
electronic energies when an electron is added or removed in accordance with the
neutral molecule. The second one is based on the differences between the HOMO
and the LUMO energies of the neutral molecule and is known as orbital-vertical
(Koopmans’ theorem). Therefore, the Koopmans’ theorem is a crude but useful and
fast approach. The behavior of electro negativity, softness and electrophilic index for
the studied molecules shows the magnitude large than these for the original ring,
adding the radicals give the molecule more softness.
Molecular electrostatic potentials (MEP)
Molecular electrostatic used extensively for interpreting potentials have been
and predicting the reactive behavior of a wide variety of chemical system in both
electrophilic and nucleophilic reactions, the study of biological recognition processes
and hydrogen bonding interactions [5].
V(r), at a given point r (x,y,z) in the vicinity of a compound, is defined in
terms of the interaction energy between the electrical charge generated from the
compound electrons and nuclei and positive test charge ( a proton) located at r.
Unlike many of the other quantities used at present and earlier as indices of
reactivity, V(r) is a real physical property that can be determined experimentally by
diffraction or by computational methods. For the systems studied the MEP values
were calculated as described previously, using the equation:
V( r) = ZA/RA-r-(r’)/ r’-rdr’
93
where the summation runs over all the nuclei A in the compound and polarization
and reorganization effects are neglected. ZA is the charge of the nucleus A, located at
RA and (r’) is the electron density function of the compound.To predict reactive
sites for electophilic and nucleophilic attack for the investigated compound,
molecular electrostatic potential (MEP) was calculated at B3LYP/6-31++G(d,p)
optimized geometries. Red and blue areas in the MEP map refer to the regions of
negative and positive potentials and correspond to the electron-rich and electron-
poor regions, respectively, whereas the green color signifies the neutral electrostatic
potential. The MEP surface provides necessary information about the reactive sites.
The electron total density on to which the electrostatic potential surface has been
mapped is shown in Fig.5, the electron density isosurface being 0.002 a.u. The
negative regions V(r) were related to electrophilic reactivity and the positive ones to
nucleophilic reactivity. As easily can be seen in Fig.6, this compound has several
possible sites for electrophilic attack in which V (r) calculations have provided in-
sights. Negative regions of V(r) are associated with chlorine and oxygen atoms of
DCH [6]. The most negative V(r) value is associated with carbon atoms in the ring of
DCH. Thus, it would be predicted that an electrophile would preferentially attack
DCH at these position. Alternatively, we found the positive regions over the
hydrogen atoms of DCH compound and indicating that these sites can be the most
probably involved in nucleophilic processes. The Fig 7 shows the molecular
electrostatic potential surface of (DCH). The colour–coded values are then projected
onto the isodensity surface to produce a three–dimensional electrostatic potential
model. Local negative electrostatic potentials (red) signal oxygen atoms with local
positive electrostatic potentials (blue) signal polar hydrogen the in ring. Green areas
cover parts of the molecule where electrostatic potentials are close to zero (C–C and
C–Cl bonds).
Conclusion
The XRD studies confirm the structural identity of the grown crystals. The HRXRD
study indicates that the grown crystal has very low angle boundary. FT-IR and FT-
Raman spectra revealed the presence of various functional groups. So we carried out
94
ab initio and density functional theory (B3LYP) calculations on the structure and
vibrational spectra of HDP. The vibrational frequencies analysis by B3LYP method
agrees satisfactorily with experimental results. On the basis of agreement between
the calculated and experimental results, assignments of all the fundamental
vibrational modes of DHC were examined and proposed. Therefore, the assignments
made at higher level of the theory with higher basis set with reasonable deviations
from the experimental values, seems to correct. HOMO and LUMO energy gap
explains the eventual charge transfer interactions taking place within the compound.
NLO property has also been observed by predicting the first hyperpolarizability for
the title compound due to the substitution in the benzene. MEP study shows that the
electrophilic attack takes place at the C5 position of HDP compound.
Table1 Crystal data and structure refinement for Dihydroxy coumarin Empirical formula C11H8O5 Formula weight (g.mol-1) 162.2 Crystal size/mm 0.40×0.21×0.18 Crystal system Monoclinic Space group P2(1)/c Unit cell dimensions a (Å) 3.8056(3) b (Å) 8.4552(7) c (Å) 11.3651(10) α (°) 90 β (°) 95.629(4) γ (°) 90 V (Å3) 363.93(5) Z 2 µ (mm−1) 0.369 Dc/g cm-1 1.48 (sinθ /λ )max/Å-1 1.08 Reflections collected 6373 R(F); Rw(F) 0.0158; 0.0145 S 1.41 Nobs/Npar 20.14 Largest difference in peak and hole (eÅ-3)
-0.203; 0.324
95
Table 2Optimized geometrical parameters of Dihydroxy coumarin by HF /6-311++G(d,p) and B3LYP/6-311++G(d,p) calculations Value (A0) Value ( 0 ) Value ( 0 )
Bond Length
HF /6-311 ++G(d,p)
B3LYP/6-311++G(d,p)
Exp Bond Angle HF /6-311
++G(d,p)
B3LYP/6-311++G(d,p)
Exp
Dihedral Angle HF /6-311 ++G(d,p)
B3LYP/6-311++ (d,p)
Exp
N6-H7 0.99 1.01 0.84
H4-O3-C18 108.3 106.5 109.4 H4-O3-C18- O2 0.2 0.3 -4.3
N6-C19 1.36 1.38 1.37
O3-C18-O2 120.1 119.8 122.2 O3-C18-C9-C10 -0.6 0.5 5.8
N6–C8 1.39 1.39 1.40
C9-C8-N6 119.2 118.9 118.8 H4-O3-C18-C9 179.9 180.0 175.5
O3-H4 0.95 0.97 0.84
C8-N6-H7 113.9 112.8 114.0 C8-N6-C19-O5 3.8 2.9 -2.0
C19-O5 1.20 1.22 1.22
C8-N6-C19 128.9 129.0 129.1 H7-N6-C19-O5 -180.0 -179.9 176.0
C19-C20
1.50 1.50 1.51
H7-N6-C19 117.4 118.3 116.0 O5-C19-C20-C28 180.0 -179.9 176.0
C25-C23
1.38 1.39 1.39
N6-C19-O5 124.4 123.6 124.7 Cl1-C25-C23-H24 0.8 0.7 -0.2
C18-O2 1.20 1.23 1.23
O5-C19-C20 120.4 120.7 121.0 Cl1-C25-C23-C21 -180.0 180.0 179.8
Cl1-C25 1.72 1.73 1.74
H29-C28-C26 117.9 117.3 119.7 Cl1-C25-C26-C28 180.0 -180.0 -0.5
Cl1- O2 1.7418 1.7556 1.42
Cl1-C25-C23 119.5 119.5 119.3 C20-C19-N6-C28 180,0 -179,9 177.2
O2- O3 1.3806 1.3911 1.53
Cl1-O2- O3 119.4057 119.3931 123.6 Cl1-O2-O3-H4 -179.7711 -179.8714
O2- H7 1.3831 1.3925 Cl1-O2- H7 119.4234 119.4678 120.7 Cl1-O2-H7-N6 -179.7807 - 179.8672 178.4 O3- H4 1.3846 1.3919 0.8
5 O3-H4 -O5 120.6348 120.7201 116.3 O2-O3-H4-O5 -0.2058 -0.0653 -
176.5 O3- C8 1.0731 1.0823 O3-H4 -C9 17.8304 117.6575 118.5 O2 -O3-H4-C9 -179.2518 -179.2295 174.4
96
H4- O5 1.3893
1.4007 H13-C12- C1 115.0855 4123.9514 H13-C12-C14-C25 174.4246 175.9823 -174.5
H4- C9 1.0741 1.0836 1.22
C12-C14-H15 128.9167 128.9882 C12-C14-H15-C16 -179.5643 -179.9669 179.4
O5- N6 1.3901 1.4 1.53
C12-C14-C25 117.1009 117.9541 H13-C12-C14-C25 174.4346 175.9823
O5- C12 1.5058 1.5054 1.28
C14-H15- C20
122.2628 122.3926 C25-C14-H15-C20 -177.5602 -178.8716
N6- C10 1.0728 1.0826 1.20
H17-C16- C26
118.3867 119.0693 H17-C16-C26-H27 -179.1265 -179.3931
H7- H11 1.0733 1.0824 1.53
C16-H17- C18
121.5012 121.3318 C16-H17-C18-H22
-179.9907 -179.9907
C12- H13
1.1946 1.221 1.10
C16-H17- C21
119.8565 118.4534 119.3 H15-C16-H17-C21
-179.5552 179.9864
C12- C14
1.3652 1.3806 H17-C18- C19
118.5303 118.9655 121.6 C26-H17-C18-C19
178.5942 179.5942
H13- H24
2.154 2.1421 H17-C18- H22
120.5065 120.294 120.7 C21-H17-C18-H22 -0.0763 -0.0971
C14- H15
1.3948 1.3956 C19-C18 -H22
120.9631 120.7405 115.3 C19-C18-H22-C20 -179.9204 -179.9204
C14- C25
0.9933 1.0156 C18-C19- C20
121.5876 121.332 C18-C19-C20-H24
179.7162 179.7709
H15- C16
1.4122 1.4264 C18-C19- C23
119.8897 119.9431 C16-C26-H27H29 -179.1265 - 179.9771
H15- C20
1.3963 1.4057 C20-C19-C23 118.5227 118.7249 C16-C26-C28-C23 179.5888 179.9888
C16- H17
1.3964 1.4053 H15- C20-C24
119.4354 118.6987
97
Table 3 HOMO - LUMO energy gap and related molecular properties of Dihydroxy coumarin.
Molecular Properties
HF/6-311++G(d,p) B3LYP/6-311++G(d,p)
HOMO -0.3204a.u -0.2626a.u
LUMO -0.0743a.u. -0.0942a.u.
Energy gap 0.2461a.u. 0.1683a.u.
Ionisation Potential (I) 0.3204 a.u. 0.26261a.u.
Electron affinity(A) 0.0743 a.u. 0.9425a.u.
Global softness(s) 8.1267a.u. 11. 8793a.u.
Global Hardness (η ) 0.1230 a.u. 0.0841a.u.
Electro negativity (χ) 0.1973a.u. 0.1784 a.u.
Global Electrophilicity (ω) 1.5821a.u. 1.0598 a.u.
Fig 1 Dimer molecular structure of Dihydroxy coumarin
98
Fig 2 ORTEP diagram with labels for atoms Dihydroxy coumarin.
Fig 3 Static deformation density maps drawn in the plane Dihydroxy coumarin.
99
Fig. 4: HOMO-LUMO plot of Dihydroxy coumarin
∆E = 0.1683a
(First excited state)
ELUMO = -0.2626 a.u
(Ground State)
EHOMO = -0.0942a.u
100
Fig 5 The total electron density surface of Dihydroxy coumarin
Fig 6 The contour map of electrostatic potential surface of Dihydroxy coumarin.
101
Fig 7 The molecular electrostatic potential surface of Dihydroxy coumarin.
Reference
[1]M. Arivazhagan, K. Sambathkumar and S. Jeyavijayan, Indian J. Pure Appl. Phys., 48
(2010) 716-722.
[2]D.Cecily Mary Glory, R.Madivanane and K.Sambathkumar Elixir Comp. Chem. 89
(2015)
36730-36741.
[3] Kuppusamy Sambathkumar Spectrochim. Acta A 147 (2015) 51-66.
[4]K. Sambathkumar, Density Functional Theory Studies of Vibrational Spectra, Homo-
Lumo, Nbo and Nlo Analysis of Some Cyclic and Heterocyclic Compounds (Ph.D.
Thesis), Bharathidasan University, Tiruchirappalli, August 2014.
[5]K.Sambathkumar and K.Settu Elixir Vib. Spec. 91 (2016) 38087-38098. [6]K.Sambathkumar and G.Ravichandran Elixir Comp. Chem. 91 (2016) 38077-38086 38077.
102
GROWTH AND CHARACTERIZATION OF POTASSIUM
THIOCYANATE DOPED POTASSIUM DI HYDROGEN ORTHO
PHOSPHATE (KSCN-KDP) CRYSTALS BY SR METHOD
B.Shalini
Department of Physics, Auxilium College, Gandhi Nagar, Vellore
ABSTRACT
Potassium thiocyanate doped potassium dihydrogen phosphate (KDP)
crystals were grown by Sankaranarayanan Ramasamy (SR) technique. The grown
crystals were characterized by powder X-Ray diffraction to find the phase and
structure of the crystals. The FTIR analysis was made to identify the functional
groups and the UV-VIS transmission studies were carried out to determine the
optical transparency of the grown crystals. And micro hardness are also determined.
Introduction :
A crystal is a three dimensional solid composed of a periodic array of atoms
i.e., a representative unit is repeated at regular intervals along any and all directions
in the crystals.[2] The beauty and sparkle of many faceted crystals found all over the
earth crust have attracted man’s interest since the beginning of recorded history.
Crystals have been attracting mankind in the past due to their aesthetic beauty.
Examples for them are the most valuable diamond to artificial stones like American
diamond. Recently, single crystals have been used extensively in solid state devices.
Today, crystals are the pillars of the modern technology. Without crystals, there
would be no electronic industry, no photonic industry, no fiber-optic
communications, very little modern optical equipment and some very important gaps
in conventional production engineering.[1]
Materials and methods: Potassium thiocyanate is the chemical compound with the
molecular formula KSCN and Potassium dihydrogen phosphate (KDP). Seed for
crystal growth were prepared by slow evaporation method. In this method, 300 ml of
double distilled water was taken in a 500 ml beaker in that KDP of 129.2855g and
KSCN of 4.859g was added. The substance (KSCN salt + KDP salt) was made to
dissolve in the solvent (water) until the formation of supersaturated solution. Then,
the highly dissolved salt solution was filtered and poured in a tray covered with a
103
plastic paper with a few small holes for evaporation of solvents. The apparatus was
placed undisturbed till sufficient size of seed crystal (KSCN + KDP) were obtained
in the tray. Finally the seeds were harvested for crystal growth as shown in the
Figure.
Seed crystal
Preparation of solution
Making up the solution is the most time consuming process. There appear to
be short cuts for obtaining a solution precisely equilibrated at a desired temperature,
but it may be helpful to mention some common pit fills. A precisely saturated
solution can never be made simply by combining the necessary amount of water and
salts as determined by solubility curves, first, because astonishingly larger amount of
published solubility data is not accurate, and second heating to complete dissolutions
introduces gross errors. Here a highly soluble KSCN doped KDP salt solution was
prepared in a 500 ml beaker by continuous stirring of KSCN doped KDP salt in
distilled water. After getting supersaturated solution, the solution was filtered and
poured in a beaker. The crystals were formed.
Solubility test: KSCN doped KDP was made to dissolve in water until the
formation of supersaturated solution. On reaching the supersaturation, the
concentration of the solute may be determined gravimetrically. A sample of the clear
super anent liquid was withdrawn by means of a warmed pipette and poured in a
petridish which has been covered with seal paper with small holes. After the
evaporation of solvent the remaining substance was weighed. The above procedure is
repeated for different temperature. Then the solubility graph was drawn.
104
Table1: Solubility of KSCN doped KDP
Temperat
ure (0C)
Solubility in
10 ml of
water (gms)
30 2.4126
35 2.6734
40 2.8928
45 3.1653
50 3.3661
Solubility diagram of KSCN doped KDP crystal at various temperatures
Harvesting the grown crystal by slow cooling method
This is the best method among others to grow bulk single crystals from solutions.
Already prepared synthesized material was taken and crushed well. The synthesized
substance was made to dissolved in solvent (water) till the formation of
supersaturated solution. Then the solution was filtered and poured in a beaker and
covered with seal paper with small holes. Crystal grown of suitable size by slow
cooling method was harvested carefully. The crystal thus obtained is shown in figure
4.4,
CON
CEN
TRAT
ION
TEMPERATURE IN oC
105
Crystal grown by slow cooling method
Harvesting the grown crystal
Crystal grown in suitable size by the Sankaranarayanan tube was harvested
carefully. The crystal thus obtained is shown in figure
Figure: Crystal grown by Sankaranarayanan method
Results and characterization: Powder XRD analysis. Powder XRD is useful for
confirming the identity of a solid material and determining crystalline and phase
purity. Figure 5.4 shows x-ray powder diffraction patterns of KSCN doped KDP.
Powder X-ray diffraction study was carried out using Rich Seifert X-ray
diffractometer with the CuKα radiation (λ = 1.5418 Å) in the range of 10 ° - 80 °, in
steps of 0.02 °. It reflects good crystallinity
of the grown crystal. The lattice
parameters were calculated using TREOR
program and the peaks were indexed using
APPLEMAN program from the observed 2
θ values. The calculated lattice parameters
shows that it belongs to tetragonal system
with the parameters a = 7.4557Å, b =7.4557Å, c = 6.9226Å, and Volume =
384.81Å, Density = 2.3325 g/cm3 the XRD spectrum of the KSCN doped KDP in
20 30 40 50 600
2000
4000
6000
8000
10000
12000
(321
)
(301
)
(220
)(1
12)
(211
)
(200
)
Inte
nsity
2 the ta
106
JCPDS 35-807. The calculated values were in best agreement with the reported
literature. The recorded spectrum is shown in fig
Figure X-ray powder diffraction pattern of KSCN doped KDP
hkl values of KSCN doped KDP were confirmed by Joint committee on powdered
diffraction studies (JCPDS).
Fourier Transform Infrared Spectroscopy analysis:
A Fourier transform infrared spectrum has been taken for the powder KDP crystal
using KBr pellet technique. The spectra were recorded in the wavelength ranges 400-
4000cm-1 and the graph is given below,
403.
1943
4.62
463.
0153
6.73
903.
98
1091
.69
1307
.4616
28.8
0
2465
.30
2929
.48
3444
.59
3653
.113692
.68
3750
.06
3783
.83
3894
.57
3994
.49
KDP
40
45
50
55
60
65
70
75
80
85
90
95
100
%T
500 1000 1500 2000 2500 3000 3500 Wavenumbers (cm-1)
Figure FT-IR spectroscopy
The functional groups of the sample have been analyzed by FT-IR spectrum.
The FT-IR spectra were recorded in the regions of 400 – 4000cm-1 using perkin-
elmer FT-IR spectrum RXI spectrometer by KBr petter technique. Figure 5.7 shows
the FT-IR spectrum of the sample. The peaks at particular wave number confirms
the functional groups of the sample. It includes O-H stretching vibrations of KDP.
Hydrogen bonding within the crystal is suggested to be cause for the broadening of
the peak. The presence of water is well supported by its bending vibrations in the
spectrum.
107
Assignment of some selected FT-IR wave numbers (Cm-1) of KSCN doped KDP.
1307.46 P=O stretching vibration, 903.98 P-O-H stretching vibration, 3614( band of
weak intensity) O-H stretching vibration, 3444.59 O-H stretching vibration,
2465.30-2929.48 (very weak band) P-O-H Symmetric stretching and bending,
536.73(very strong band) HO-P-OH bending vibrations.
UV visible analysis
200 300 400 500 600 700 800 900nm
KDP
0.00.51.01.52.02.53.03.54.04.55.0Abs
Figure UV-Visible absorption spectrum
The UV-visible absorption spectrum of the sample was recorded in solution
form using water solvent in the ratio of 1:1 (water : ethanol ). Fig. shows UV-visible
absorption spectrum of the sample. The cut off wavelength was observed at 250nm
and there was no significant visible spectrum in the range of 300 to 900nm.[7]
Internal structure of KSCN doped KDP crystal
Figure 5.11 Internal structure of KSCN doped KDP crystal
108
Internal structure of KSCN doped KDP crystal were found by using optical
microscope. In these figure number of pits and also voids are present.
Measurement of microhardness
Measurement of microhardness measurement of KSCN doped KDP crystal
Conclusions
Potassium thiocyanate doped potassium dihydrogen phosphate (KSCN doped
KDP) crystals were grown by Sankaranarayan Ramasamy (SR) technique. In general
KDP single crystals were grown by slow evaporation techniques but the crystals
grown by this method were much smaller in size. The KSCN doped KDP bulk single
crystal were also grown by slow cooling method. Potassium thiocyanate doped
potassium dihydrogen phosphate was synthesized and purified and the nucleation
parameters like solubility were determined. The solubility curves indicate high
solubility of KSCN doped KDP in water with a positive solubility temperature
gradient. Structure of the crystal were determined by XRD technique. The functional
groups in the grown crystal were confirmed by FT-IR analysis. The absorbance
ranges of the crystal were found by UV-visible spectrum. Microhardness values of
the crystal were also measured.
References:
[1] Book entitled “ Crystal growth processes and method” by Dr. P. Santhanaraghavan, and Dr.P.Ramasamy (1990), Kumbakonam
[2] Engineering physics by Dr.P.Mani,Dhanam publications, june 2005.
Load (gm)
Vicker’s microhardness
Hv(Kg/mm2)
109
[3]”The growth of single crystals” by R.A.Laudise, Eaglewood cliffs,1970.
[4]”Crystal growth process” by J.C.Brice, Halsted press, 1986.
[5]Center of crystal growth, SSN college of engineering, SSN Nagar, Kalavakkam
603110,India.
[6] Guohui Li, Xue Liping, Genbo Su, Xinxin Zhuang, Zhengdong Li, Youping He,
Journal of Crystal Growth, 274 (2005) 555-562.
[7] S. Balamurugan, P. Ramasamy Spectrochimica Acta Part A 71 (2009) 1979-
1983.
[8]A.P.voronov,Yu.T.Vyday,V.I.Salo,V.M.Puzikov,S.I.Bondarenko Radiation
measurements 42 (2007) 553-556.
[9] P.V. Dhanaraj, N.P Rajesh, C.K Mahadevan, G. Bhagavanarayana, Physica B
404 (2009) 2503-2508.
[10] Yusuke Asakuma,Shingo TAKEDA, kouji Maeda,Keisuke Fkui Applied
surface science 255 (2009) 4140-4144.
[11] Y. Enqvist, J. Partanen, M. Louhi-kultanen, J. Kallas, Chemical Engineering
Research and Design, 81 (2003) 1354-1362.
[12]Hartman. P, Structure and morphology in crystal growth.
[13]Genesa Moorthy.S, Joseph kumar. F, Subramaniyan, C, and Ramasamy .P
Structure of NLO Material.
[14]X-ray powder Diffraction (XRD) by Barbara L Dutrow, Louisiana State
university,Christine M. Clark, Easterrn Michigan university
[15]Material science and process by R.S.Khurmi and R.S.Sedha (1987).
110
Structural and Optical Studies of Wolframite Metal Tungstates (M2+ Wo4;
M=Co & Ni Synthesizes via Sonochemical Precipitation Technique
A. Sampathu1, K. Ravichandran1*
1Department of Nuclear Physics, University of Madras, Chennai, Tamilnadu, India
Corresponding Author Email: [email protected]
Abstract
Ni and Co doped metal tugstates (WO4) were synthesised by simple and cost
effective sonochemical method. XRD results showed the well crystalline nature with
monoclinic structure of Ni and Co doped WO4. From HRSEM micrograph, it is seen
that the nanocube morphology of the synthesised samples with less agglomeration.
The optical band gap has been found by the Tauc’s plot for the both samples, is 2.8
eV. It is clearly shows that the there is no variation in bandgap with doping of Ni and
Co in WO4. From the PL analysis it is conclude that the NiWO4 have possess the
excellent optical features over CoWO4 . NiWO4 is a great candidate for
optoelectronic applications.
Keywords: Metal tungstates, Nanocube, Bandgap, WO4.
1.0. INTRODUCTION
Recently, ternary oxide semiconductors that are M2+WO4 with the wolframite
crystal structure have been received much attention due to their technological
properties such as higher values of thermal stability, refractive indexes,
ferroelasticity, ionic conductivity and X-ray absorption coefficients [1-3]. Because of
its intriguing luminescence and structure properties, the metal tungstate is an
attractive material for photonics and photoelectronics. In these applications it is
important to study their optical band gap very accurately. However, earlier reports
show wide dispersion in the band gap and there was no agreement has been
observed. Till date wolframite structured metal tungstates of CdWO4, ZnWO4,
NiWO4, CoWO4 and MnWO4 are known for their wide applications in conventional
111
catalysis, or as scintillator material, in photoluminescence, optical fibres and as
materials in microwave technology [4–8]. Besides the above, the metal tungstates
were used as photocatalyst for removal of various organic pollutants from the water.
As a p-type semiconductor, CoWO4 has been widely investigated for optical devices
and photoluminescence materials [9]. It is well known that optical behaviour is
particle size dependent, therefore it should controlled through typical synthetic
conditions. According to the earlier reports many methods have been reported
including conventional ceramic method, sol-gel, hydrothermal and precipitation
technique. Among them chemical precipitation method is most widely used due to
their adequate synthetic conditions and cost effective for large scale production.
From the earlier reports it can be understandable that, in addition to the host
material, the dopant also play a vital role for luminescence efficiency. However, the
energy transfer and typical electronic transition and site symmetry of the host
material is still not clear and it needs further investigations.
In this present study we are interested to investigate the optical band gap and
luminescent characteristic NiWO4 and CoWO4 nanostructure. The optical response
of CoWO4 and NiWO4 was studied. The origin of characteristic band gap variation
and their luminescence were discussed.
2.0. Experimental
2.1. Synthesis of NiWO4 and CoWO4
Cobalt acetate (Co2+CH3COO-) and nickel acetate (Ni2+CH3COO-) are dissolved
in deionized water separately under sonication path for 15min.The pre-prepared
disodium tungstates (Na2WO4) solution were dropped in to above precursor solution
followed by sonication for 1h. After that stirring continued for 4h and followed the
aging for 12h. As obtained precipitates were washed well through the centrifugation
with DI water, ethanol and acetone several times and dried at room temperature
.Final products were calicined at 500°c for 4 h. Further, the synthesised powders
were investigated by X-ray diffraction analysis (XRD), High Resolution Scanning
112
Electron Microscope (HRSEM), UV-Vis spectroscopy and Photoluminescence
studies.
3.0. Result and discussion
3.1. X-Ray diffraction analysis
The structural properties were observed by XRD. From the Fig.1, it is seen that
prepared samples of diffraction peaks are assigned well to the wolframite like
monoclinic crystal structure. The lattice parameters of the metal tungstate’s are
found and tabulated in Table.1. Observed lattice parameters are well matched with
the Joint Committee on Powder Diffraction Standards (JCPDS); card #72-0480 and
#15-0867 for NiWO4 and CoWO4respectively. There is no additional peaks were
found in the XRD pattern. The average crystallite size was estimated from the XRD
peaks using Scherer Equation (1).
Where β is the full width half-maximum and λ is the wavelength of the X-ray.
The measured d values are in the 50 nm for CoWO4 and 80nm for NiWO4. These
values are fairly agreed with the FESEM. It is seen that from the Fig 1(b) the lattice
parameters little bit alter by doping of Ni and Co due to lattice distortion between
dopants and metal tungstate.
Table l. Calculated lattice parameters and Crystallite size
Lattice parameters ( )
Samples a b c
Crystallite
Size
(nm)
CoWO4 4.949 5.680 4.686 50
NiWO4 4.73 5.70 4.950 80
113
Fig 1. (a) XRD pattern of the CoWO4 and NiWO4. (b) Lattice parameters
variation with doping of CoWO4 and NiWO4.
3.2. HRSEM Analysis
The surface morphology of the NiWO4 and CoWO4 nanostructure was
analysed using HRSEM. Captured HRSEM images of the samples calcined at 500
°C for 4 h are shown in Fig.2(a-d). It can be seen that the particles are in present in
the shape of round edged cubical morphology with uniform distribution. When
compared to CoWO4, the NiWO4 nanoparticles have shown well resolved
morphology with less agglomeration. This is due to the strong crystalline features of
the material. Observed average particle sizes are in the range of 40-55 and 50-79 nm
for CoWO4 and NiWO4 respectively. This concludes that, with respect the
experimental technique and synthetic conditions it is possible to tune the
morphology. By tuning the morphology of the material there is possible to change
their optical and luminescent features which are necessary for opto-electronic
devices applications.
(a) (b)
114
Fig 2. HRSEM Micrograph
3.3. UV-Vis Spectra Analysis
The optical absorption spectra of NiWO4 and
CoWO4wolframite heat treated at 500 °C is illustrated
in Fig. 3. Broad UV absorption maximum at around
270-300 nm, were observed for both the tungstate
sample which confirms the unique optical behaviour of
the material and it is associated to the direct charge
transfer between ligand and metal within the (WO42-)
groups [10&12]. It can be seen that the strong UV
absorption edge with extended tail to higher wavelength in the UV-Vis spectra
represents the presence of localized energy bands.In the excited state of the (WO42-)
groups, the hole (on the oxygen) and the electron (on the tungsten) remain together
a b
c d
Fig 3
115
as an exciton because of their strong interactions [11]. Further absorption peaks in
the visible region are exhibited by NiWO4 which could be due to a charge transfer
transition in which an oxygen 2p electron goes into one of the empty tungsten 5d
orbital [11&12]. Similarly, for CoWO4the absorption band appeared at above 500
nm belongs to the d-d transition of octahedrally coordinated Co2+ ions in the CoWO4
nanostructure [13].With the strong UV absorption generally localized inter-atomic
excitation was observed at visible region and which is mainly due to d-d transition
on Co2+ [13].
Optical band gap of the prepared samples have been calculated by Tauc’s plot
using absorption as well as reflectance spectra from the following relation,
αhν = A(hν-Eg)n (2)
where in equation (2) α is the absorption coefficient, h is the Plank’s constant, v is
the photon energy, Eg is the band gap energy and n is a transition coefficient which is
1/2 and 2 for allowed direct transitions and indirect transitions respectively. Figure
3.4 represents the tauc plots of as prepared NiWO4 and CoWO4 nanostructure. The
linear extrapolation of the plot at α=0 corresponds to the energy band gaps of the
samples. Interestingly, both the material has shown the almost same optical energy
gaps as well which confirms the well quality
crystalline features of the material.
The estimated Eg value is ~2.8 eV as
shown in Fig 4 and which is in good
agreement with the earlier reports. The
observed band gap energy for NiWO4 is
slightly lower than the Rosiyah Yahya el al
and Tiziano Montini report [11&12].
Fig: 4 Tauc’s plot of CoWo4 and NiWo4
116
3.4 Photoluminescence Studies
Figure 3.5 shows the PL spectra of NiWO4 and CoWO4cubical nanostructure
annealed at 500 °C for the excitation of 220 nm at room temperature. The broad blue
emission was observed at around 420-455 nm without any hump or shoulder. This is
corresponds to the radiative transition of [WO4]2- tetrahedrons. The intrinsic
luminescence is caused by the annihilation of a self-trapped exciton, which formed
excited [WO6]6- complex. This can be excited either in the excitonic absorption band
or in the recombination process due to wolframite-structured products [14].
Although, there is no change in the emission band position due to the Ni2+ or
Co2+cations. However the relative PL intensity has been decreased drastically for
CoWO4. In general, the synthetic conditions, crystallinity and morphology of the
materials are strongly influences on the luminescence [15-19]. Therefore it is
important to control the particle size as well as morphology in order to increase the
luminescent efficiency. At 500 °C calcination there is low intense emission was
observed due to the less crystalline and aggregated surface morphology in the
CoWO4. In the case of NiWO4 the well crystalline nanocubes are present and thus
increase the PL intensity significantly. This is associated to the formation of good
quality crystalline NiWO4 with well-defined
nano cubical morphology with less
aggregation. Thus enhance the PL intensity
of the NiWO4 nanostructure than the
CoWO4. From the PL analysis it is conclude
that the NiWO4 have possess the excellent
optical features over CoWO4. It can be the
potential candidate for future optical devices
applications.
Fig. 5 photoluminance spectrum of
CoWo4 and NiWo4
117
4.Conclusion
Cowo4 and NiWo4 were successfully synthesised by sonochemical
precipitation technique. The XRD pattern revealed monoclinic phase and no
secondary peaks were conformed. The Clear morphology of nanocubes with round
edge crystals are observed from the High resolution scaning electron microscopy.
UV visible spectrum showed the absorption in the UV region. The band gap energy
were found by Tauc’s plot for as prepared Cowo4 and NiWo4. The strong UV-
absorption with extended tail in the UV-Vis spectra for both the tungstates
demonstrates the excellent optical behaviour of the wolframite nickel and cobalt
tungstates nanostructures. At 220 nm excitation wavelength, the strong PL emission
peak was centred at 420-455 nm regions for both the samples. In comparison to
CoWO4, the relative intensity of the emission band of NiWO4 nanocubes is
increased. This is due to the good quality and well crystalline natures of the NiWO4,
it leads to increase in luminescent intensity with the desired optical features.Ni
doped Wo4 nanostructure synthesised by sonochemical method highly appealing
material for optoelectronic devices.
References
1. Rajagopal S., Nataraj D., Khyzhun O. Yu., YahiaDjaoued, Robichaud J.,
Mangalaraj D.,Hydrothermal synthesis and electronic properties of FeWO4 and
CoWO4 Nanostructures, Journal of Alloys and Compounds,2010, Vol. 493, pp.
340–345.
2. Rajagopal S., Bekenev V.L., Nataraj D.,Mangalara jD.,Khyzhun O. Yu.,
Electronic structure of FeWO4 and CoWO4tungstates: First-principles FP-LAPW
calculations and X-ray spectroscopy studies, Journal of Alloys and Compounds,
2010, Vol. 496, pp. 340–345.
3. Scott H.P., Williams Q., and Knittle E., Ultralow compressibility silicate without
highly coordinated silicon, Phys. Rev. Lett., 2002, Vol. 88, pp.015506-015509.
4. Meddar L., Josse M., Deniard P., La C., Andre G., Damay F., Petricek V., Jobic
S., Whangbo M.-H., Maglione M., Payen C., Effect of nonmagnetic substituents
118
Mg and Zn on the phase competition in the multiferroicantiferromagnet MnWO4,
Chem. Mater., 2009, Vol. 21, pp. 5203-5214.
5. Zhen L., Wang W.-S., Xu C.-Y., Shao W.-Z., Qin L.-C., A facile hyrothermal
route to large-scale synthesis of CoWO4nanorods, Mater. Lett., 2008, Vol. 62, pp.
1740-1742.
6. Kuzmin A., Purans J., Kalendarev R., Pailharey D., Mathey Y., XAS, XRD,
AFM and Raman studies of nickel tungstate electrochromic thin films
Electrochim. Acta, 2001, Vol. 46, pp. 2233-2236.
7. de Oliveira A.L.M., Ferreira J.M., Silva M.R.S., de Sousa S.C., Vieira F.T.G.,
Longo E., Souza A.G., and Santos I.M.G., Influence of the thermal treatment in
the crystallization of NiWO4 and ZnWO4 J. Therm. Anal. Calorim., 2009, Vol.
97, pp. 167-172.
8. YuS.-H., Antonietti M., Cölfen H., and Giersig M., Angew. Chem. Int. Ed. 2002,
Vol. 41, pp. 2356.
9. Irina Kärkkänen, MargusKodu, Tea Avarmaa, JelenaKozlova, Leonard Matisen,
Hugo Mändar,Agu Saar, V.Sammelselg, RaivoJaaniso,Sensitivity of CoWO4
Thin Films to CO, Procedia Engineering,2010, Vol. 5 pp. 160–163.
10. Fang Lei, Bing Yan, and Hao-Hong ChenSolid-state synthesis, characterization
and luminescent propertiesof Eu3+-doped gadolinium tungstate and molybdate
phosphors:Gd(2-x)MO6:Eux3+ (M =W, Mo), Journal of Solid State Chemistry,
2008, Vol. 181, pp. 2845–2851.
11. SitiMurni M Zawawi., RosiyahYahya., Aziz Hassan., H N Mahmud.,
Mohammad Noh Daud., Structural and optical characterization of metal
tungstates (MAWO4; M=Ni, Ba,Bi) synthesized by a sucrose-templated method,
Chemistry Central Journal, 2013, Vol. 7, pp. 80.
12. TizianoMontini, ValentinaGombac, Abdul Hameed, Laura Felisari,
GianpieroAdami and Paolo Fornasiero, Synthesis, characterization and
photocatalytic performance of transitionmetal tungstates,Chemical Physics
Letters, 2010, Vol. 498 pp. 113–119.
119
13. Zuwei Song, Junfeng Ma, Huyuan Sun, Wei Wang,Yong Sun, Lijuan Sun,
Zhengsen Liu and Chang GaoSynthesis of NiWO4nano-particles in low-
temperaturemolten salt medium, Ceramics International, 2009, Vol. 35, pp.
2675–2678.
14. Naik S.J., and Salker A.V., Solid state studies on cobalt and copper
tungstatesnano materials, Solid State Sciences, 2010, V0l. 12, pp. 2065-2072.
15. Naik S. J., Uma Subramanian, Tangsali R. B.,and Salker A.V., Optical absorption
and photo luminescent studies of cerium-doped cobalt tungstate nanomaterials, J.
Phys. D: Appl. Phys., 2011, Vol. 44, pp. 115404 (7).
16. Thresiamma George, Sunny Joseph, AnuTresa Sunny and Suresh Mathew.,
Fascinating morphologies of lead tungstate nanostructures by chimiedouce
approach, J Nanopart Res, 2008, Vol. 10, pp. 567–575.
17. Yonggang Wang, Junfeng Ma, Jiantao Tao, Xiaoyi Zhu, Jun Zhou, Zhongqiang
Zhao, LijinXie and HuaTian., Low-temperature synthesis of CdWO4nanorods via
a hydrothermal method, Ceramics International, 2007, Vol. 33, pp. 1125–1128.
18. TitipunThongtem, AnukornPhuruangrat and SomchaiThongtem., Preparation and
characterization of nanocrystalline SrWO4 using cyclic microwave radiation,
Current Applied Physics, 2008, Vol. 8, pp. 189–197.
19. Jeong Ho Ryu, Jong-Won Yoon and Kwang Bo Shim., Blue luminescence of
nanocrystalline PbWO4 phosphor synthesized via a citrate complex route assisted
by microwave irradiation, Solid State Communications, 2005, Vol.133, pp. 657.
120
Effect of Fe on Cerium Oxide Nanoparticles
A.AArthi, P. Vijayashanthi, S. Shanmuga Sundari*
Department of Physics, PSGR Krishnammal College for Women, Coimbatore.
*Corresponding author mail id: [email protected]
ABSTRACT
Cerium oxide is one of the most important rare earth material and has been
widely investigated because of its multiple applications, such as a catalyst, an
electrolyte material of solid oxide fuel cells, a material of high refractive
index, and an insulating layer on silicon substrates. In the present work pure and 0.5
mol% of Fe doped cerium oxide nanoparticles have been prepared by co-
precipitation method at 300 K in which ammonia was added as precipitating agent
and FeCl3 as dopant. Crystalline nature and crystallite size were calculated from
XRD and it is found that it decreases after incorporation Fe in CeO2 lattice. The
absence of secondary peaks confirms a complete solid solution of Fe and CeO2,
Direct and indirect band gap were calculated from UV-Vis spectra. Surface
morphology was studied by SEM. Magnetic characteristics were analyzed from
VSM .
1. INTRODUCTION:
Ceria is a fluorite-structured rare earth oxide. Cerium oxide is a cheap and
widely used rare earth material. Cerium oxide (ceria) is an important material for the
application to practically used polishing agents [1], sunscreens [2], solid electrolytes
[3], and automotive exhaust catalysts [4]. Recently, ultrafine nano particles have
attracted much attention due to the physical and chemical properties that are
significantly different from those of bulk materials. Many studies have been carried
out to obtain ceria single nano particles smaller than 10 nm [5]. As reported, various
techniques based on the chemical wetness routes have been extensively used to
prepare CeO2 nano particles, such as hydrothermal [6,7], reverse micelles [8], sono
chemical [9], pyrolysis [10] and homogeneous precipitation [11–15] . Cerium oxide
also has optical properties, high thermal stability and electrical conductivity and
diffusivity. For all these cases, nano structured CeO2 has attracted much attention
121
due to improvements in the redox properties, transport properties and surface to
volume ratio with respect to bulk materials [16]. The method described here is based
on a coprecipitation synthesis. Fabricating CeO2 nano particles by co precipitation
method is due to advantages of low cost, mild synthesis condition and easy scale-up.
Precipitation method is a kind of wet-chemical methods through which the grains
with small size. The grain size of the products depends on the solubility of
precipitate, i.e the smaller the precipitate solubility, the smaller the grain size. In the
present work ceria and 1 mol of Fe doped paricles were prepared by co
precipitation method and the prepared samples were characterized by X-ray
diffraction (XRD), Scanning electron microscopy (SEM), Fourier transformation
infrared spectroscopy (FT-IR), ultraviolet and visible spectroscopy (UV–vis),
photoluminescence spectrum (PL), vibrating sample magnetometer(VSM).
2. EXPERIMENTAL TECHNIQUES:
CeO2 nano particle were synthesized using by coprecipitation method. 50ml
of Distilled water was used as solvent and the chemicals used were analytical reagent
grade. Cerium nitrate hexahydrate is used as starting material. Cerium nitrate
hexahydrate was dissolved in distilled water, in a clear solution after 1hr the dopent
1 mol % FeCl3 was added. The clear solutions suddenly change into transparent
brown solution. 25ml of ammonia was added to the solution as a precipitating agent.
Brown precipitates was formed all of a sudden and stirred for 8 hrs continuously to
get a clear solution. The solution was centrifuged for 45 min and washed with water
and ethanol subsequently. The collected particles were dried at 100 oC for hours.
The prepared particles were analysed using XRD, FTIR, SEM, UV-vis, PL and VSM
3. RESULT AND DISCUSSION:
3.1.XRD ANALYSIS:
Figure 1 show the X-ray diffraction patterns of pure (S1) and 1 mol. % of Fe-
doped CeO2 (1M). It reveals that there are several crystalline peaks at 2θ values of
28.22˚, 33.00˚, 47.17˚, 56.07˚, 69.02˚, 77.01˚ and 88.23˚. The corresponding hkl
planes of [111], [200], [220], [311], [400], [331] and [422]. All diffraction patterns
can be indexed as CeO2 with cubic fluorite structure in the JCPDS card no. 34-0394.
122
The XRD patterns of the peak were broad, suggesting the relatively small particles.
From the X-ray diffraction pattern of the samples, the average crystallite size of the
sample can be estimated by the Scherrer equation,
D = Kλ/β cosθ (1)
where D is the crystallite size of the sample, K is the Scherrer shape factor, here
K=0.9; λ is the wavelength of X-ray CuKα (λ =0.154nm), β is the full-width at half-
maximum (FWHM) in radian and θ is the Bragg angle of the X-ray diffraction peak.
Table .1. shows the lattice parameter and crystalline size of S1 and 1M nanoparticles.
Fig.1.X-ray diffraction patterns of S1and 1M nanoparticles
Table.1Particle size and lattice constant of S1 and 1 M
Sample Particle size D in (nm) Lattice constant a in Å
S1 7-7.4 5.4
1M 4.4-6.6 5.4
3.2. FT-IR ANALYSIS:
Fig.2. presents the FT-IR spectrum of S1 and 1M nanoparticles in the range
from 4000 cm-1to 400 cm-1 and the peak assignments are listed in Table 2.
123
Table.2 FTIR peak assignments of S1 and 1 M
S1 band
position
1M-
band
position
Band assignment Functional group
3447 3412 O-H stretch,H-bonded alcohols
2884 C-H stretch Alkanes
2803 H-C=O: C-H stretch Aldehydes
2253 -C≡C-strech Alkynes
1737 C=O strech carbonyls (general)
1542 N-O asymmetric stretch nitro compounds
1401 C-C stretch Aromatics
1362 C-H rock Alkanes
1333 N-O symmetric stretch Nitro compounds
1216 C-O stretch alcohols, Carboxylic
acids,esters,
833, 634 C-CI strech Alkyl halides
Fig.2. FT-IR spectrum of S1 and 1M nanoparticle
124
3.5. SCANNING ELECTRON MICROSCOPE
The SEM images of the pure and doped (1mol %) CeO2 nanoparticles are
shown in the Fig.3. The undoped and FeCl3 doped CeO2 nanoparticles having
uniform spherical like structure. The e doped particles are smaller than pure one
Fig.3.SEM Image of pure (S1) and FeCl3(1mol %) doped CeO2 nanoparticle
3.4. ULTRA-VOILET VISIBLE SPECTRAL ANAYSIS:
Fig.4.shows the UV Visible absorption spectrum of S1 and 1M nano particles in the
rang 200 nm to 2200 nm. The absorption bands are corresponds to electron
excitation from the valence band to conduction band, and be can be used to
determine the nature and value of the optical band gap. Optical band gap is obtained
using the following equations.
α(hν) = A(hν –Eg)m/2 (2)
where, A is a constant and Eg is the band gap of the material and exponent n depends
on the type of transition. For direct allowed transition n = 2, indirect allowed
transition n=1/2. To measure the energy band gap value from the absorption spectra,
a graph (αhγ)2 versus (hγ) is plotted and the values are listed in Table 3.
125
Fig.4 UV-vis spectra of S1 and 1M nanoparticle.
Table.3. Band gap values for S1 and 1 M
SAMPLE DIRECT BANDGAP INDIRECT
BANDGAP
S1 2.84 eV 2.65eV
1M 1.61 eV 1.44 eV
3.5. PHOTOLUMINOSCENCE ANALYSIS
The PL spectrum of the S1 and 1M nanoparticles are shown in the Fig.5. The
intensity of the peak
decreased after the
addition of Fe and blue
shift was observed which
indicates the reduction in
particle size.
Fig.5. PL spectrum of S1 and 1M nanoparticles
126
4. CONCLUSION:
Ceria and Fe doped cerium oxide nanoparticles were synthesized by co-
precipitation method. The synthesized nanoparticles are subjected to X-ray
diffraction technique to analyse the structure. The FT-IR spectrum of the sample is
recorded and the characteristic absorption bands are observed. Bandgap energy
calculated from the uv-vis. SEM analysis show regular spherical like particles.
Reference
[1] J . B. Hedrick and S . P . Sinha, J. Alloys Compd. 207/208 (1994) 377.
[2] T. Masui, M. Yamamoto, T. Sakata, H. Mori and G. Adachi, J. Mater. Chem.10
(2000) 353.
[3] H. Inaba and H. Tagawa, Solid State Ionics 83 (1996) 1.
[4] A. TrovarellI, Catal. Rev. Sci. Eng. 38 (1996) 439.
[5] G. ADACHI and N. IMANAKA, Chem. Rev. 98 (1998) 1479.
[6] N.C. Wu, E.W. Shi, Y.Q. Zheng, W.J. Li, J. Am. Ceram. Soc.85 (2002) 2462.
[7] M. Hirano, E. Kato, J. Mater. Sci. Lett. 15 (1996) 1249.
[8] T. Masui, K. Fujiwara, K.I. Machida, G.Y. Adachi, T. Sakata, H. Mori, Chem.
Mater. 9 (1997) 2197.
[9] L. Yin, Y. Wang, G. Pang, Y. Koltypin, A. Gedanken, J. Colloid Interface Sci.
246 (2002) 78.
[10] H. Xu, L. Gao, H. Gu, J. Guo, D. Yan, J. Am. Ceram. Soc. 85 (2002) 139.
[11] X.D. Zhou, W. Huebner, H.U. Anderson, Appl. Phys. Lett. 80 (2002) 3814.
[12] E. Matijevic´, W.P. Hsu, J. Colloid Interface Sci. 118 (1987)506.
[13] P.L. Chen, I.W. Chen, J. Am. Ceram. Soc. 76 (1993) 1577.
[14] J.G. Li, T. Ikegami, Y. Wang, T. Mori, J. Am. Ceram. Soc. 85 (2002) 2376.
[15] N. Uekawa, M. Ueta, Y.J. Wu, K. Kakegawa, Chem. Lett. 2002; 854.
[16] C.-W. Sun, H. Li, H.-R. Zhang, Z.-X. Wang, L.-Q. Chen, Nanotechnology 16
(2005) 1454.
127
GROWTH AND CHARACTERIZATIONS OF (TRI) GLYCINE BARIUM
CHLORIDE SINGLE CRYSTAL FOR OPTOELECTRONICS AND
PHOTONICS APPLICATIONS
S. Chennakrishnan1, D. Sivavishnu2, T. Kubendiran2, S.M. Ravi Kumar2* 1 Department of Physics, Idhaya Arts & Science College for women, Tiruvannamalai
606 705 2 PG & Research Department of Physics, Government Arts College, Tiruvannamalai
606 603, *Corresponding author: [email protected]
ABSTRACT
The single crystal of (tri) glycine barium chloride, a semiorganic crystal has been
grown from an aqueous solution by slow evaporation technique at room
temperature. Glycine and barium chloride were used in molar ratio of 3:1 for
synthesis. Good optical quality single crystal of size 18×10×5 mm3 was harvested
in a period of 35 days at pH value 5. The lattice parameters have been measured by
single crystal XRD study. Fourier transform infrared (FTIR) spectroscopy study
confirmed the presence of functional groups in grown crystal. The thermal
behavior of the crystal was investigated by TG-DTA analysis, which reveals that
crystal has thermally stable up to 169ºC. Non-linear optical property of the grown
crystal has been confirmed using the Kurtz and Perry powder technique and result
was compared with KDP.
1.Introduction
Non-linear optics is an emerging field as it extends the usefulness of lasers by
increasing the original frequency of incident radiation. Non-linear optical (NLO)
materials are capable of producing higher values of the original frequency and,
hence, this phenomenon can find applications in optical modulation, fiber optic
communication, photonics and opto- electronics [1-3]. In recent years, many
researchers have tried to find varieties of NLO materials for laser applications. The
complexes of organic material with inorganic acids and salts are promising materials
for second harmonic generation (SHG) as they tend to combine the features of
organic with that of inorganic materials. In general, organic materials are showing a
good efficiency for SHG but poor mechanical and thermal properties. It is difficult to
128
grow large size crystals with good optical quality of these materials for device
applications [4]. Most of the amino acids and their complexes are the family of
organic and semiorganic non-linear optical (NLO) materials that have potential
applications in second harmonic generation (SHG), optical storage, optical
communication, photonics, electro-optic modulation, optical parametric amplifiers,
and optical image processing [5-10].
Also amino acids are interesting materials for NLO applications due to the
fact that the carboxylic acid group donates its proton to the amino group to form a
salt of the structure CH3CHCOO-NH3+. Thus in solid state, amino acid exists as
dipolar ion in which carboxyl group is present as carboxylate ion. Due to this dipolar
nature, amino acids have promising physical properties which make them ideal
candidate for NLO applications. Recently, the amino acid group materials were
mixed with organic or inorganic salts in order to improve their chemical stability,
laser damage threshold, thermal, physical properties and linear and non linear optical
properties.
Glycine (NH2-CH2-COOH) is the simplest amino acid. Unlike other amino
acids, it has as symmetric carbon atom and is optically inactive. It has three
polymeric crystalline forms α, β and γ, in which α-glycine is commonly available.
Glycine mixed with metal chlorides such as zinc chloride [11], calcium chloride
[12], potassium chloride [13], sodium chloride [14], lithium chloride [15] have been
reported in the recent years. Interest have been centered on semiorganic crystal
which have the combined properties of both inorganic and organic crystals like high
damage threshold, wide transparency range, less deliquescence, higher mechanical
strength and chemical stability which make them suitable for device fabrication [16].
The advantage of including semiorganic material is to grow from aqueous solution
and forms a large three dimensional crystal of excellent physico-chemical properties.
Hence, it is necessary to synthesize and grow novel semiorganic crystals which have
positive aspects of both organic and inorganic.
In this present investigation we report bulk growth (tri) glycine barium chloride
crystal by solution growth technique. The grown crystals were characterized using
single crystal XRD and powder X-ray diffraction, fourier transform infrared (FT-IR)
analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and
129
UV-vis spectroscopy. Optical constants like refractive index, reflectance, extinction
coefficient and electric susceptibility and also dielectric constant, dielectric loss and
photoconducting nature have been determined for the first time.
2. Experimental Procedure
2.1 Synthesis
The compound (tri) glycine barium chloride was synthesized by reacting
glycine (Merck, GR grade) barium chloride (Merck, GR grade) with stoichiometric
ratio of 3:1. A necessary quantity of glycine is taken in a beaker and dissolved in
double distilled water at room temperature until it attains a saturated condition. After
preparing saturated solution of glycine, the proportionate amount of barium chloride
was added with continuous well stirring for 4 hours to bring a homogenous mixture
of solution. The (tri) glycine barium chloride was synthesized on the following
chemical reaction.
3(NH2-CH2-COOH) +BaCl2 Ba(NH2-CH2-COO)3Cl
2.2 Crystal growth
Recrystallization was carried out to eliminate any impurities in the (tri) glycine
barium chloride crystal. The recrystallized salt was used for the preparation of
saturated solution. The saturated solution was filtered using whattman filter paper to
remove impurities. This super saturated solution was tightly covered with
polyethylene sheet, to keep out dust before it was allowed to evaporate at room
temperature. After 15 to 20 days good quality seed crystals were obtained. The good
quality and defect free seed crystal was selected for bulk growth. The (tri) glycine
barium chloride crystal of average
dimension 18×10×5 mm3 has been
harvested in the period of 25 to 35 days
and the grown crystals are highly
transparent. As grown crystal of (tri)
glycine barium chloride is shown in
Figure 1.
Figure 1 As grown crystal of (tri) glycine barium chloride
130
3432
.73
3062
.56
2981
.59
2898
.36
2698
.10
2589
.49
2039
.15
1571
.73
1478
.33
1404
.45
1330
.91
1116
.77
1031
.78
896.
38
668.
43
100015002000250030003500Wavenumber cm-1
9394
9596
9798
9910
0Tr
ansm
ittan
ce [%
]
3 Results and discussion
3.1 Single crystal X-ray diffraction
Single crystal X-ray diffraction analysis of (tri) glycine barium chloride was
recorded using ENRAF NONIUS CAD-4 diffractometer. The calculated lattice
parameters are a=8.281Ǻ, b=9.410 Ǻ, c=14.898 Ǻ, α=β=γ=90º and volume V=
1160.177 Ǻ3 which confirm the orthorhombic crystal system with non-
centrosymmetric space group pbcn.
3.2 Fourier Transform Infrared (FTIR) spectroscopy study
The infrared spectral analysis is effectively used to understand the chemical
bonding and provides information about molecular structure of the synthesized
compound. Crushed powder of (tri) glycine barium chloride was pelletized using
KBr. The spectrum was recorded using a Thermo Nicolet V-200 FTIR Spectrometer
in the range 400-4000 cm-1 wavenumber region. The FTIR spectrum of (tri) glycine
barium chloride is shown in Figure 2. The peaks around 3432 cm-1 is due to NH
asymmetric stretching. The peaks obtained at 2981, 2698 cm-1 for CH stretching.
The peaks of IR spectrum at 2689, 2589 cm-1 is due to NH3+ stretching vibration.
The peaks around 1571 cm-1 is due to NH3+ deformation. A peak at 1478 cm-1 has
been assigned to NH2 deformation vibration. A peak 1404 cm-1 is due to COO-
symmetric stretching. The peak at 1330 cm-1 is due to C-N-H symmetric bending.
The peak around 1116 cm-1 is due to CH2 rocking. A peak at 1031 cm-1 for C-C-N C
symmetric stretching. The peaks at 896 and 668 cm-1 are due to C-CN stretching and
C-Cl stretching respectively.
The band assignments for
corresponding wavenumber
of FTIR spectrum of (tri)
glycine barium chloride are
presented in Table 1.
Figure 2. The FTIR spectrum of (tri) glycine barium chloride
131
200 400 600 800 1000
0
20
40
60
80
100
Tran
smitt
ance
%
Wavelength (nm)
Table 1. Band assignments of FTIR spectrum of (tri) glycine barium
chloride.
Wavenumber cm-1 Assgnments 3432 NH asymmetric 3062 NH2 stretching
2981, 2898 CH stretching 2698, 2589 NH3
+ stretching 1571 NH+
3 deformation 1478 NH2 deformation 1404 COO- symmetric 1330 C-N-H symmetric 1116 CH2 rocking 1031 C-C-N C symmetric 896 C-CN stretching 668 C-Cl stretching
3.3 Optical transmission study
The optical transmission spectrum was recorded using DOUBLE BEAM UV-
Vis Spectrophotometer:2202 in the region 200-1000 nm and the optical transmission
spectrum of
(tri) glycine barium chloride is shown in Figure 3. The transmission is maximum in
the entire visible region and infrared region. In (tri) glycine barium chloride, the UV
transparency cut-off wavelength lies at 234 nm and the percentage of transmission is
high in the entire visible region from 234 nm to 1000 nm. The absence of absorption
in the entire visible region makes the triglycine barium chloride crystal as a potential
candidate for second harmonic generation and various applications [18].
Figure 3. Optical transmission
spectrum of (tri) glycine barium
chloride crystal
3.4 TGA/DTA annalysis
Thermal properties of the
material was studied by
Thermogravimetric (TGA) and Differential
Thermal Analysis (DTA) using STA 409 C instrument between the temperature 50
132
and 800 ºC at a heating rate of 20 ºC per min in the nitrogen atmosphere. (Tri)
glycine barium chloride sample weighing 4.237 mg was taken for the measurement.
TGA and DTA curve of (tri) glycine barium chloride crystal is shown in the Figure
4. DTA curve shows a sharp endothermic peak at 169.3 ºC which corresponds to the
melting point of the compound. Hence the thermal stability of (tri) glycine barium
chloride is around 169 ºC. The absence of water of crystallization in the molecular
structure is indicated by the absence of weight loss around 100 ºC. The
material decomposes at 321.8 ºC, which is represented by the sudden loss of the
mass. The weight loss is due to the decomposition of glycine. Above 321.8 ºC, the
material undergoes irreversible endothermic transition around at 500 ºC. From the
TG curve, the mass loss takes place after the temperature of 169.3 ºC. The mass lost
from 169 ºC to 321 ºC is found to be 43% which is the sublimation of the Cl. There
is further mass loss of 7% occuring in the temperature limit of 321-500 ºC which
involve the evolution of NH3. The actual residual amount of mass is 50% which
may be considered to be the compound of barium. From the above analysis, the
melting point of the (tri) glycine barium chloride is 169 ºC which is higher than the
other semiorganic materials like bis-glycine hydrogen chloride (146.8 ºC ), tetra
glycine barium chloride (160 ºC), α-glycine sulpho-nitrate (143 ºC) [22-24].
T e m p C e l8 0 0 .07 0 0 .06 0 0 .05 0 0 .04 0 0 .03 0 0 .02 0 0 .010 0 .0
DTA
uV
4 5 .0 0
4 0 .0 0
3 5 .0 0
3 0 .0 0
2 5 .0 0
2 0 .0 0
15 .0 0
10 .0 0
5 .0 0
0 .0 0
-5 .0 0
-10 .0 0
TG %
10 0 .0
9 0 .0
8 0 .0
7 0 .0
6 0 .0
5 0 .0
4 0 .0
3 0 .0
2 0 .0
10 .0
0 .0
16 9 .3Ce l5 .3 6uV 321 .8Ce l
4 .3 3uV
5 .3%
43 .0%
Figure 4. TG/DTA curve of (tri) glycine barium chloride crysta
133
3.5 Kurtz powder SHG test
In order to confirm the non-linear optical property of powdered sample of
(tri) glycine barium chloride was subjected to KURTZ and PERRY techniques,
which remains powerful tool for initial screening of materials for SHG efficiency
[19]. A Q-switched Nd: YAG laser emitting 1.06µm with power density up to 1
GW/cm2 was used as a source of illuminating the powder sample. The sample was
prepared by sandwiching the graded crystalline powder with average particle size of
about 90µm between two glass slides using copper spices of 0.4 mm thickness. A
laser was produced a continuous laser pulses repetition rate of 10Hz. The
experimental setup uses a mirror and 50/50 beam splitter. Here well known NLO
crystal KDP is taken as a reference material.
The fundamental beam was splitted into two beams by the beam splitter (BS);
one of them was used to illuminate the powder under study and the other constituted
the reference beam of power Pω. Half-wave plate (HW) placed between two parallel
polarizers (P) and was used to pump the beam power. The input power was fixed at
0.68 J and the output power was measured as 4.4 mJ, which was compared to output
8.8 mJ of standard KDP. The diffusion of bright green radiation of wave
lengthλ=532 nm (P2ω) by the sample confirms second harmonic generation (SHG).
The powder SHG efficiency of (tri) glycine barium chloride crystal was about 0.5
times of KDP. The good second harmonic generation efficiency indicates that the
(tri) glycine barium chloride crystals can be used as a suitable material for non-linear
optical devices.
4.0 Conclusion
Well developed good quality transparent crystal of (tri) glycine barium chloride
was grown successfully by slow evaporation technique. Unit cell constants and
crystal system were determined by single crystal X- ray diffraction technique
confirmed the identity of the synthesised material. Powder XRD shows good
crystallinity of the grown crystal. The various functional groups presence in the
grown crystal was identified by FTIR study. The UV cut off wavelength of (tri)
glycine barium chloride crystal is found to be around 234 nm, which reveals grown
crystal is potential candidate for NLO applications. The optical bandgap (Eg),
134
absorption coefficient (α), extinction coefficient (K) was also calculated from UV
spectrum. The thermal analysis shows the melting point of grown sample is 169 ºC.
The powder SHG analysis shows that the efficiency of crystal is 0.5 times than that
of KDP.
REFERENCE
1.B. Narayana Moolya, A. Jayarama, M.R. Sureshkumar, S.M. Dharmaprakash,
Hydrogen bonded nonlinear optical gamma-glycine: Crystal growth and J.
Crystal Growth 280(2005) 581-586.
2. T apati Mallik, Tanusree Kar, Synthesis, growth and characterization of a new
nonlinear
optical crystal: l-arginine maleate dehydrate, Cryst.Res Technol. 40 (2005)
778-781.
3.Kandasamy, R. Siddeswaran, P. Murugakoothan, S.P. Kumar, R. Mohan,
Synthesis, Growth, and Characterization of l-Proline Cadmium Chloride
Monohydrate (l-PCCM) Crystals: A New Nonlinear Optical Material, Cryst.
Growth Des. 7 (2007) 183-186.
4.K. Ambujan, K. Rajarajan, S. Selvakumar, I. vetha potheher, G.P. Joseph, P.
Sgayaraj Growth, Optical, Dielectric and Fundamental Properties o NLO active
L-histidinium Perchlorate Single Crystals, J. Crystal.Growth 286 (2006) 440-444.
5.D. Eimerl, S. Velsko, L. Davis, F. Wang, G. Loiacona, G. Kennedy, Deuterated L-
arginine phosphate: a new efficient nonlinear crystal, IEEE Quantum Electron. 25
(1989) 179-193.
6.K. Meera, R. Muralidharan, R. Dhanasekaran, Prapun Manyum, P. Ramasamy,
Growth of nonlinear optical material: L-arginine hydrochloride and its
characterization, J. Cryst.Growth 263 (2004) 510-516.
7.M. Vimalan, A. Ramanand, P. Sagayaraj, Synthesis, growth and characterization of
l-alaninium oxalate - a novel organic NLO crystal, Cryst.Res. Technol. 42 (2007)
1091-1096.
8.K. Kirubavathi, K. Selvaraju, R. Valluvan, N. Vijayan, S. Kumararaman,
Synthesis, growth, structural, spectroscopic and optical studies of a new
semiorganic nonlinear optical crystal: l-Valine hydrochloride, Spectrochimica.
Acta part A 69 (2008) 1283-1286.
135
9.S.B. Monaco, L.E. Davis,S.P. Velsko, F.T. Wang, D. Eimerl, A.J. Zalik, Synthesis
and characterization of chemical analogs of L-arginine phosphate,
J.Cryst.Growth 85 (1987) 252-255.
10. C.Justin Raj, S. Dinakaran, S. Krishnan, B. Milton Boaz, R. Robert, S. Jerome
Das, Studies on optical, mechanical and transport properties of NLO active l-
alanine formate single crystal grown by modified Sankaranarayanan–Ramasamy
(SR) method, Optics Commun. 281 (2008) 2285-2290.
11. T. Balakrishnan and K. Ramamurthi, Growth, structural, optical, thermal and
mechanical properties of glycine zinc chloride single crystal, Materials
Letters,62 (2008)65-68.
12. M. Ayanar, J. Thomas Joseph Prakash, C. Muthamizhchelvan and S. Ponnusamy,
Journal of Physical Sciences,13 (2009) 235-244.
13. S. Palaniswamy and O.N. Balasundaram,Rasayan, Growth and characterization of
semi-organic nlo material: glycine potassium chloride (GPC), J.Chem,2 (2009)
28-33.
14. S. Palaniswamy and O.N. Balasundaram,Rasayan, Effect of ph on the growth and
Characterization of glycine sodium chloride (GSC) single crystal,J.Chem,1
(2008) 782-787.
15. R. Varatharajan and Suresh Sagadevan, Studies on the mechanical properties of
glycine lithium chloride NLO single crystal, International Journal of Physical
Sciences,8(39) (2013)1892-1897.
16. J. Qin, D. Liu, C. Dai, C.Chen, B. Wu, C.Yang, C.Zhan, Influence of the
molecular configuration on second-order nonlinear optical properties of
coordination compounds Coord.Chem.Rev 188 (1999) 23-34.
17. M.D. Aggarwal, J. Choi, W.S. Wang, K. Bhat, R.B. Lal, A.D. Shields, B.G. Penn,
D.V. Frazier, Solution growth of a novel nonlinear optical material: L-histidine
tetrafluoroborate, J.Cryst.Growth 204 (1999) 179-182.
18. R. Christian, solvents and solvent effects in organic chemistry, VCH, New York,
1990.
19. Kurtz and perry. A Powder Technique for the Evaluation of Nonlinear Optical
Materials,
Journal of Applied Physics, Vol. 39(1968) 3798-3813.
136
Measurement of Natural Radioactivity and Assessment of Radiological Hazards
in Coastal sediments of Cuddalore Coast, Tamilnadu, India
K. Thillaivelavan1, N. Harikrishnan2, G. Senthilkumar3, R. Ravisankar2* 1Department of Physics, Periayar Arts College, Cuddalore 607 001, Tamilnadu,
India 2Post Graduate and Research Department of Physics, Government Arts College,
Thiruvanamalai 606603,Tamilnadu, India 3Department of Physics, University College of Engineering Arni, Arni 632317,
Tamilnadu, India
E-Mail: [email protected]; Tel : +91-9443520534
Abstract
Natural and artificial radionuclide pollutants of the marine environment have
been recognized as a serious environmental concern. In the present work, the natural
radioactivity levels in beach sediment samples collected from Thazhankuda to
Rasapettai, of Cuddalore Coast, Tamilnadu have been determined using gamma ray
spectrometry. The activity concentration of 238U, 232Th, and 40K in sediment samples
was measured by NaI (Tl) detector. The average specific activities for 238U, 232Th
and 40K were found to be 7.202, 31.474 and 328.716 Bq kg-1 respectively.. The
average activity of 238U, 232Th and40K is lower when compared with worldwide
average value.The results have been compared with other radioactivity
measurements in different countries. The radiation hazard due to the total natural
radioactivity in the study area was estimated using radiation indices such as absorbed
dose rate (DR), annual effective dose equivalent (AEDE) and external hazard indices
(Hex) and they are compared with the international recommended values and safety
limits. The values of radiation hazard parameters are below the recommended
values. Therefore, coastal sediments are unlikely to pose radiological health risk to
the people living in nearby the study area.
Keywords: Natural Radioactivity, Sediment, Gamma Ray Spectrometry,
Radiological Hazards
137
1.0. Introduction
Naturally occurring radioactive materials generally contain terrestrial origin
radionuclides (primordial radionuclides), left over since the creation of the earth
(UNSCEAR, 1982). They are typically long lived with half lives of about hundreds
of millions of years. Gamma radiation emitted from natural sources (background
radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series and
their decay products, as well as 40K, which exist at trace levels in the earth’s crust.
The knowledge of the concentrations and distributions of these radionuclides are of
interest since it provides useful information in the monitoring of environmental
contamination by natural radioactivity.
The concentration of radionuclides in marine sediments can provide very
useful information on the source, transport mechanisms and environmental fate of
radionuclides. A considerable attention has been given, to allow the creation of
scientific database of the radiological baseline levels on the coastal region of the
study area using γ-ray spectrometry. Obtaining activity concentrations of natural
radionuclides are useful for radiation risk assessment. The baseline data can be used
to assess any changes in the radioactivity background level due to various activities
involving radioactive materials or any fallout in the near future. The measurement
will also help in the development of standards and guidelines for use.
Natural radioactivity measurements in coastal sediments in different parts of
the world were reported by many authors [Orgun et al ., (2007); Arogunjo et al.,
(2004); Saad andAl-Azmi, (2002); Uosif et al.,(2008); Alam et al.,(1999);
Ravisankar et al., (2014); Chandramohan et al., (2015)]. To our knowledge, there
seems to be no information about radioactivity level in and around Cuddalore coast,
Tamilnadu. In this study, the gamma radiation has been measured to determine
natural radioactivity of 238U, 232Th and 40K in coastal sediment samples from
Thazhankuda to Rasapettai, Cuddalore of East Coast of Tamilnadu.
2.0. Materials and methods
2.1. Sample collection and Preparation
Sediment samples were collected along the Bay of Bengal coastline, from
Thazhankuda to Rasapettai coast of Cuddalore Dist, Tamilnadu during pre-monsoon
138
condition. Table-1 represents the geographical latitude and longitude for the
sampling locations at the study area.
Table 1. Geographical latitude and longitude for the sampling locations of the
study area
S
No. Sample ID Area Name Longitude Latitude
1 CTZ Thazhamguda 11°45'58.9932"N 79°47'16.4652"E
2 CDP Devanampattnam 11°44'47.9724"N 79°47'0.3876"E
3 CSK Sonankuppam 11°43'26.6556"N 79°46'50.2968"E
4 CKI Kori 11°42'35.7084"N 79°46'40.2060"E
5 CRP Rasapettai 11°40'56.2692"N 79°46'17.5008"E
Sampling locations were
selected to cover the shore area
as uniformly as possible
Sediments were collected at a
depth of about 10 cm by a Grab
sampler. Each sample of about 2
kg was kept in a thick plastic
bag. The collected samples were
air dried at room temperature in
open air then brought to the
laboratory, where they were
dried for 12 hours in an oven at
105˚C to constant mass. Then
pebbles, leaves and other foreign
particles were removed. Sediment samples were sieved with a 250 micron mesh
laboratory test sieve. Samples were then stored for a period of 4 weeks to allow
radioactive equilibrium to be attained between 238U (226Ra) and 232Th (228Ra) and
their progenies. The sample location map is shown in Fig-1.
139
2.2. Gamma ray spectrometric analysis
Measurements of the activity concentrations of 238U, 232Th and 40K in Bq kg-1
dry weight of the collected samples were carried out with a counting time of 10,000
secs using gamma-ray spectrometry. A 3" x 3" NaI (Tl) detector was employed with
adequate lead shielding whichreduced the background by a factor of about 95%. The
concentrations of various radionuclides of interest were determined in Bq kg–1 using
the count spectra. The gamma ray photo peaks corresponding to 1.46 MeV (40K),
1.76 MeV (214Bi) and 2.614 MeV (208Tl) were considered in arriving at the activity
of 40K, 238U and 232Th in the samples. The detection limit of NaI(Tl) detector system
for 40K, 238U and 232Th are 8.50, 2.21 and 2.11 Bq kg–1 respectively for a counting
time of 10, 000 secs.
3.0. Results and Discussion
3.1. Activity concentrations of 238U, 232Th and 40K in the sediments
The activity concentrations of 238U, 232Th and 40K in the sediment samples are
given in Table-2. All values are given in Bq kg-1 of dry weight. The activities range
and mean values (in brackets) for 238U, 232Th and 40K are ≤ 2.21 - 19.82 (7.20), ≤
2.11 - 101.43 (31.47) and 292.75- 387.14 (328.71) Bq kg-1 respectively. The wide
variations of the activity concentration values are due to their presence in the marine
environment and their physical, chemical and geo chemical properties (Khatir et al.,
1998, El Mamoney et al., 2004). The results show that the mean activity of 238U and 40K is lower whereas 232Th is slightly higher than when compared with worldwide
average values (35 Bq kg−1 for 238U, 30Bq kg−1 for 232Th and 400 Bq kg−1 for 40K,)
(UNSCEAR, 2000). Table-3 lists the activity concentration of different parts of the
world. Fig-2 shows the variation of activity concentration at different sampling
locations.
Fig- 2. Variation of activity concentration (Bq kg-1) at different sampling
locations
140
Table 2
Activity concentration (Bq kg-1), Absorbed Gamma Dose Rate (DR), Annual
Effective Dose Rate (AEDR), and External Hazard index (Hex) in coastal
sediments
Activity Concentration
Bq Kg-1 S.
No
Sample
ID 238U 232Th 40K
Absorbed
Gamma
Dose Rate
(DR)
nGy h-1
Annual
Effective
Dose
equivalent
(AEDE)
External
Hazard
index
(Hex)
1 CTZ 9.56 13.21 292.75 24.638 0.030 0.138
2 CDP 19.82 101.43 319.26 83.424 0.102 0.512
3 CSK BDL 18.92 303.38 25.115 0.030 0.142
4 CKI BDL 21.71 341.05 28.371 0.034 0.161
5 CRP BDL BDL 387.14 18.541 0.022 0.095
Average 7.20 31.47 328.71 36.018 0.044 0.209
Table 3
Comparison of activity concentration of present work with other
countries
Activity concentration (Bqkg-1) S. No. Name of the Location
238U 232Th 40K References
1 Ezine region, Turkey 290 532 1160 Orgun et al., (2007)
2 Nigeria 16 24 35 Arogunjo et al., (2004)
Saudi Coastline 3 (Gulf of Aqaba)
11.4 22.5 641.1 Al-Trabulsy et al., (2011)
4 Turkey(Firtina River) 16-113 17-87 51-
1605 Kurnaz et al., (2007)
5 Bangladesh 19 37 458 Alam et al., (1999)
6 Cuddalore Dist, Tamilnadu, India 7.20 31.47 328.71 Present work
141
4.0. Evaluation of radiological hazard effects
4.1. Absorbed gamma dose rate (DR)
The greatest part of the gamma radiation comes from terrestrial radionuclides.
It is the first major step for evaluating the health risk and is expressed in gray (Gy).
The contribution of natural radionuclides to the absorbed dose rate in air (DR)
depends on the natural specific activity concentration of 238U, 232Th and 40K. The
conversion factors used to compute absorbed gamma dose rate (DR) in air per unit
activity concentration in Bq kg-1 (dry weight) corresponds to 0.462 nGy h-1 for 238U,
0.604 nGy h-1 for 232Th and 0.042 nGy h-1 for 40K.
DR (nGy h-1) = 0.462 AU+ 0.604 ATh + 0.042 AK------------------- (1)
Where, AU, ATh and AK represent the activity concentrations of 238U, 232Th
and 40K in Bq kg-1 respectively in the samples. Using the above equation DR had
been calculated and tabulated (Table-2).The absorbed dose rate values ranged
between 18.541 and 83.424, with a mean value of 36.018 nGy h-1. This mean value
is less than the world average absorbed dose rate value of 84 nGy h-1.This indicates
that the area monitored can be regarded as having normal dose level. Fig-3 shows the
variation of absorbed gamma dose rate (DR)with different locations.
Fig- 3. Absorbed Gamma Dose Rate (DR) with Different Locations
4.2. Annual effective dose rate (AEDE)
The annual effective dose rate (AEDE) in mSv y−1resulting from the absorbed
dose values (DR) was calculated using the following formula (UNSCEAR, 2000;
Ravisankar et al., 2012):
142
Ann. Eff. dose rate(mSvy−1) = DR(nGyh−1) ×8760h × 0.7 SvGy-1 × 0.2 × 10-6
AEDE = DR × × 0. 00123------------------- (2)
The annual effective dose (Table-2) ranged between 0.022 mSv y−1to 0.102
mSv y−1with a mean value of 0.044 mSv y−1.In normal background areas, the
average annualindoor effective dose from terrestrial radionuclides is0.46 mSv y−1
(UNSCEAR, 1993). Therefore, the obtained mean value from this study
(0.044 mSv y−1) is lower than the world average value. This indicates that the
sediment samples satisfy the criteria for a radiation safety point of view. Fig- 4
shows the variation of annual effective dose equivalent (AEDE) in different
locations
Fig- 4. Annual Effective Dose equivalent (AEDE) with Different Locations
4.3. External hazard index (Hex)
According to Beretka and Mathew, (1985) the external hazard index due to
gamma radiation was calculated using below formula which is given in Eq. (3)
----------------- (3)
Where AU, ATh and AK are the activity concentrations of 238U, 232Th and 40K
in Bq kg-1 respectively. The results of Hex are reported in Table-2. The Hex value of
the present work ranged between 0.095 and 0.512 with an average value 0.209. The
average Hex value (0.209) is very much lower when compared to the acceptable limit
of unity (Hex<1). It indicates that radiation hazards may not cause any harmful to
143
people living in the study area. Fig-5 shows the variation of external hazard index in
different locations.
Fig- 5. External Hazard Index (Hex) with Different Locations
5.0. Conclusion
(i) The activity concentrations of238U, 232Th and40K in sediments collected from
Thazhankuda to Rasappetai, Cuddalore, East coast of Tamilnadu had been
determined.
(ii) Using the activity concentrations of these radionuclides, radiological
hazard indices were evaluated in order to determine the effects ofthe natural
radionuclides in sediments.
(iv) The result indicates that average value of the each radiological hazard
parameter is well below the approved and recommended safety limits.
(v) From the analysis, there is no potential radiological health hazard may
directly be associated with the sediments from Thazhankuda to Rasappetai, East
coast of Tamilnadu.
(v) The results may be used as a reference data for monitoring possible
radioactivity pollutions in future.
Acknowledgement
Authors are highly indebted to Dr. B. Venkatraman, AD, RSEG, Indira
Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu for
permitting to do radioactivity analysis in his Division.
144
References
Abdi, M.R., Hassanzadeh, S., Kamali, M., Raji, H.R., 2009. 238U, 232Th, 40K and 137Cs activityconcentrations along the southern coast of the Caspian Sea, Iran.
Marine PollutionBulletin. 58, 658-662.
Alam, M.N.,Chowdhury,M.I.,Kamal,M.,Ghose,S.,Islam,M.N.,Mustafa,M.N.,Miah,
M.M.H., Ansary,M.M., 1999.The 226Ra,232Th and 40K activatesinbeachsand
mineralsandbeachsoilsofCox’s bazaar,Bangladesh.J.Environ.Radioact.46,
243-250.
Al-Trabulsy,H.A.,Khater,A.E.M.,Habbani,F.I.,2011.Radioactivitylevelsand
radiological hazardindicesattheSaudicoastlineoftheGulfofAqaba.Radiat.
Phys.Chem.80,343–348.
Arogunjo, A.M., Farai, I.P., Fuwape, I.A., 2004. Dose rate assessment of terrestrial
gammaradiation in the delta region of Nigeria. Radiat. Prot. Dosim. 108, 73-
77.
Beretka, J., Mathew, P.J., 1985. Natural radioactivity of Australian building
materials.Industrial wastes and by products. Health Phys. 48, 87-95.
Chandramohan,J., Tholkappian, M., Harikrishnan, N., Ravisankar, R.,
2015.Assessment of Activity Concentrations of Radionuclides from
Pattipulam to Devanampattinam of East Coast of Tamilnadu, India using
Gamma Ray Spectrometry. International Journal of Frontiers in Science and
Technology. 3(3), 59-68.
El-Mamoney, M.H., Khater, A.E.M., 2004. Environmental characterization and
radioecological impacts of non nuclear industries on the Red Sea coast. J.
Environ. Radioact. 73,151–168.
Khatir, S.A., Ahamed, M.M.O., El-Khangi, F.A., Nigumi, Y.O., Holm, E., 1998.
Radioactivitylevels in the Red Sea coastal environment of Sudan. Marine
Pollution Bulletin 36,19-26.
Kurnaz, A., Ku cu ko merog lu, B., Keser, R., Okumusoglu, N.T., Korkmaz, F.,
Karahan, G.,Cevik, U., 2007. Determination of radioactivity levels and
hazards of soil and sedimentsamples in Firtina Valley (Rize, Turkey). Appl.
Radiat. Isot. 65, 1281–1289.
145
Orgun, Y., Altinsoy, N., Sahin, S.Y., Gungor, Y., Gultekin, A.H., Karaham, G.,
Karaak, Z.,2007. Natural and anthropogenic radionuclides in rocks and beach
sands from Ezineregion (canakkale), Western Anatolia, Turkey. Appl. Radiat.
Isot. 65, 739-747.
Ravisankar, R., Chandrasekaran, A., Vijayagopal, P., Venkatraman, B.,
Senthilkumar, G.,Eswaran, P., Rajalakshmi, A., 2012. Natural radioactivity in
soil samples of YelagiriHills, Tamil Nadu, India and the associated radiation
hazards. Radiat. Phys. Chem. 81,1789-1795.
Ravisankar, R., Sivakumar, S., Chandrasekaran, A., PrincePrakashJebakumar, J.,
Vijayalakshmi, I., Vijayagopal, P., Venkatraman, B., 2014. Spatial
distribution of gamma radioactivity levels and radiological hazard indices in
the East Coastal sediments of Tamilnadu, India with statistical approach.
Radiation PhysicsandChemistry. 103, 89-98.
Saad, H.R., Al-Azmi, D., 2002. Radioactivity concentrations in sediments and their
correlationto the coastal structure in Kuwait. Appl. Radiat. Isot. 56, 991-997.
UNSCEAR., United Nations Scientific Committee on the Effects of Atomic
Radiation, 1982.Sources, effects and risks of ionizing radiation. Report to the
General Assembly, withannexes, United Nations, New York.
UNSCEAR., United Nations Scientific Committee on the Effects of Atomic
Radiation,2000.Sources, effects and risks of ionizing radiation. Report to the
General Assembly withannex B, United Nations, New York.
Uosif, M.A.M., El-Taher, A., Abbady, G.E., 2008. Radiological significance beach
sand usedfor climate therapy from Safaga, Egypt. Radiat. Prot. Dosim. 131,
331-339.
Veiga, R., Sanches, N., Anjos, R.M., Macario, K., Bastos, J., Iguatemy, M., Aguiar,
J.G.,Santos, A.M.A., Mosquera, B., Carvalho, C., BaptistaFilho, M.,
Umisedo, N.K., 2006.Measurements of natural radioactivity in Brazilian
beach sands. Radiat. Meas. 41, 189- 196.
146
SYNTHESIS AND CHARACTERIZATION OF NANO ALUMINA
BY TOP DOWN APPROACH
S. Vasudevan1 and P. Kavithamani2
1,2Dept. of Physics, Shanmuga Industries Arts and Science College, Tiruvannamalai
ABSTRACT
The alumina powder size reduced using planetary ball milling equipment
from micro to nano, this is confirmed by using scanning electrons microscope.
The hardness of the nano powder sintered samples offers the improved results
than micro particle sintered sample due to its reduced particle size without
damage. The density and porosity also offers the improved results in the nano
powder sintered samples due to the presents of less voids, close packed
arrangement of particles. The co-efficient of thermal expansion on the nano
alumina sintered samples shows improved results than micro alumina sintered
sample. The nano alumina sintered samples (pin or ball) will be suitable to
investigate the tribological property with or without temperature effect. Because
nowadays there is a new challenge to improve the tribological property by
synthesis the existing hard ceramics with respect to the temperature effects.
1. INTRODUCTION
Natural materials such as organic matter, mineral matter, and living
matter, along with artificial materials produced industrially, make up all of the
materials found on the Earth. They all have a chemical composition and
particular structure that give them specific properties or functions in relation to
their surroundings or their formation conditions.
Natural materials are formed in a particular environment, under the diverse
conditions seen in nature. These materials can be studied either in their original
state or after being modified. An artificial material is a compound manufactured
by synthesis under known conditions that are selected to give it specific
properties related to its field of application. Metal alloys, ceramics, and polymers
are some simple artificial materials. New materials are often made of complex
structures composed of mixed or composite materials [1-10].
147
When studying a material, the microscopist is confronted by the
relationships between its physical, chemical, thermal, and dynamic histories. The
conditions the material was subjected to will dictate its particular microstructure
formation at different scales, and thus its physical, chemical, and/or biological
properties. Regardless of the material type, three main parameters can be
presented such as (i) microstructure, (ii) growth related to its surroundings and
(iii) properties, which are interdependent [2]. If just one of these parameters
changes, then the other two are disrupted, sometimes irreversibly. The challenge
in developing new materials is to master all of the parameters of this system in
order to reproduce the properties or functions needed for a specific application.
Diverse materials result from the natural evolution of a rock, mineral, organic
material, or biological material or from the synthetic process for man-made
materials. In addition, the mechanisms of growth or formation are different
depending on whether materials are found in the solid state or liquid state or in
intermediary solid–liquid states [3]. Depending on the conditions of temperature,
pressure, chemical gradient, kinetics of diffusion (atomic, ionic, or molecular
diffusion), and thedynamics of the system, microstructures can be very diverse in
materials science.
2. MATERIALS AND METHODS :
2.1. MATERIALS:
Alumina is one of the most cost effective and widely used materials in the
family of engineering ceramics. The raw materials from which this high
performance technical grade ceramic is made are readily available and reasonably
priced, resulting in good value for the cost in fabricated alumina shapes. With an
excellent combination of properties and an attractive price, it is no surprise that
fine grain technical grade alumina has a very wide range of applications.
Aluminum oxide, commonly referred to as alumina, possesses strong ionic
interatomic bonding giving rise to its desirable material characteristics [11-12]. It
can exist in several crystalline phases which all revert to the most stable
hexagonal alpha phase at elevated temperatures. This is the phase of particular
interest for structural applications.
148
Alpha phase alumina is the strongest and stiffest of the oxide ceramics. Its
high hardness, excellent dielectric properties, refractoriness and good thermal
properties make it the material of choice for a wide range of applications [3].
High purity alumina is usable in both oxidizing and reducing atmospheres to
1925°C. Weight loss in vacuum ranges from 10–7 to 10–6 g/cm2.sec over a
temperature range of 1700° to 2000°C. It resists attack by all gases except wet
fluorine and is resistant to all common reagents except hydrofluoric acid and
phosphoric acid. Elevated temperature attack occurs in the presence of alkali
metal vapors particularly at lower purity levels.
The composition of the ceramic body can be changed to enhance particular
desirable material characteristics [8]. An example would be additions of chrome
oxide or manganese oxide to improve hardness and change color. Other additions
can be made to improve the ease and consistency of metal films fired to the
ceramic for subsequent brazed and soldered assembly.
Nanostructured materials are a broad class of materials, with microstructures
modulated in zero to three dimensions on length scales less than 100 nm.
These materials are atoms arranged in Nano sized clusters, which become the
constituent grains or building blocks of the material. Conventional materials
have grains sizes ranging from microns to several millimeters and contain several
billion atoms each. Nanometer sized grains contain only about 900 atoms each.
As the grain size decreases, there is a significant increase in the volume
fraction of grain boundaries or interfaces. This characteristic strongly
influences the chemical and physical properties of the material.
2.2. SYNTHESIS METHODS :
Synthesis is the act of combining elements to form something new. It is called
synthesis. Today synthesis of nanomaterial is a good challenge for achieving the
size controlled synthesis. Nanoscale materials are defined as a set of substances
where at least one dimension is less than approximately 100 nanometers. In
general there are two types of synthesis were followed in synthesizing nano-
materials.
Top-down approach
Bottom-up approach
149
Nanomaterials deal with very fine structures: a nanometer is a billionth of a
meter. This indeed allows us to think in either the ‘bottom up’ or the ‘top down’
approaches to synthesize nanomaterials, i.e. either to assemble atoms together or
to dis-assemble (break, or dissociate) bulk solids into finer pieces until they are
constituted of only a few atoms [13]. This domain is a pure example of
interdisciplinary work encompassing physics, chemistry, and engineering up to
medicine.
2.2.1. DENSITY AND POROSITY :
If an object is immersed in a fluid (a liquid or a gas), its apparent weight
will be less than its real weight by an amount equal to the weight of the fluid it
displaces. This is commonly referred to as Archimedes’ principleand is the
principle of buoyancy [1-7].
Wc = Wa - Ww
Where,Wc is the apparent weight of the object in the fluid (water),
Wais the real weight of the object in air, and
Ww is the weight of the displaced fluid (water).
The balances used in the lab are calibrated in mass units. However, they actually
respond to weight, the force of gravity acting downward on the object which is
placed on the balance. Since mass is linearly related to weight by w = mg, a
balance can be calibrated in grams.
2.2.2. DILATOMETER
A dilatometer is a scientific instrument that measures the length change of
a material as a function of change in temperature. Dilatometers are valuable tools
in the investigation of ceramics, particularly when measuring the dimensional
changes that occur upon sintering.
2.2.3. SCANNING ELECTRON MICROSCOPE (SEM)
Scanning electron microscopy (SEM) is a method for high-resolution
imaging of surfaces. The SEM uses electrons for imaging, much as a light
microscope uses visible light. The advantages of SEM over light microscopy
include much higher magnification (>100,000X) and greater depth of field up to
100 times that of light microscopy. Qualitative and quantitative chemical analysis
150
information is also obtained using an energy dispersive x-ray spectrometer (EDS)
with the SEM [4].
3. RESULTS AND DISCUSSION
The milled powders were characterized by scanning electrons microscope
at 30kev in the zooming range of 60,000X. But even though the particle was not
clearly reveal the edges, when the scanning electron microscope image was taken
in back scattered electron mode. This is due to the particle collision and high
charges applied on the surfaces, shows the white color presents more. When the
energy charges applied similar to the commercial un-milled powder (15Kev),
even though the particles not reveals clearly. In range to increasing the energy the
particle reveals clearly in the same place at the same zooming range. The shape
of the particle is evenly broken, this is due to the addition of process control
agent as a stearic acid.
Figure 3.1. (1) Alumina powder before milling, (2) Alumina powder after
milling, (3, 4) Alumina powder morphology of after milling at different energy
level
The tungsten carbide tools having more hardness when compared with
alumina, results improved size reduction rate. The mechanical milling parameters
like ball to powder ratio, milling speed are the reason for improved size
reduction. Because ball to powder ratio 10:1is offers the improved particle
151
breakage. Where the ratio between ball to powder increases the tool damage
occurs, decreases the size reduction rate gets reduced, also the milling speed of
250rpm is influenced on particle size reduction rate [14]. Because the speed
increases the balls are rotate in the top of the jar, when speed reduced the
breakage rate also gets reduce. Influence of process control agent on ball milling
of nano particle for even fracture achieved.
The sintering temperature is influenced on the nano particle joining to form a solid, also the holding time of 2hrs offers improved strength. Where the atmosphere cooling causes the formation of surface layer to reduce the properties [15]. Density of the sintered samples shows the nano particulates samples offers improved density then micro particulate samples, also the porosity level is high in the micro particulate samples. It is due to the particle size, presents of more voids between the particle arrangements [16]. The nano particulates offers the improved results of density and porosity, where compared to fully dense one.
Table: 1 Physical property of micro and nano sintered alumina
The hardness value of the nano particulate sample shows higher than micro samples. It is due to the reduced voids, porosity and closed arrangement of particulates, where compared with micro particulate samples. The Dilatometer results also offered the improved results on nana particulate samples. It is due to the particle size, when the particle size reduces the co-efficient of thermal expansion also gets reduce [17-19].
Table: 2 Thermal property of micro nano sintered alumina
S.no Temperature
(k)
Micro alumina
thermal expansion
(%)
Nano alumina
thermal expansion
(%)
1 423 6.73 6.68
2 473 6.78 6.71
3 523 6.86 6.75
4 573 6.95 6.8
S.no Sample
name
Density
(g/cm3)
Porosity
(%)
Vickers hardness
(Hv)
1 Micro
sample 3.82 0.04 1597
2 Nano
sample 3.91 0.01 1612
152
4. CONCLUSION
The planetary ball milling equipment was used to reduce the alumina
powder size from micro to nano, this is confirmed by using scanning electrons
microscope. While mechanical milling the milling parameters were influenced
the size reduction without particle damage from its initial condition. The stearic
acid is influenced on the cold welding on the particle breakage, also avoids the
agglomeration of the particles. The milling speed (250rpm) and balls to powder
(10:1) ratio contributes the particle fracture rate. The hardness of the nano
powder sintered samples offers the improved results than micro particle sintered
sample due to its reduced particle size without damage. The density and porosity
also offers the improved results in the nano powder sintered samples due to the
presents of less voids, close packed arrangement of particles. The co-efficient of
thermal expansion on the nano alumina sintered samples shows improved results
than micro alumina sintered sample.
From the above obtained conclusions, this nano alumina sintered samples
(pin or ball) will be suitable to investigate the tribological property with or
without temperature effect. Because nowadays there is a new challenge to
improve the tribological property by synthesis the existing hard ceramics with
respect to the temperature effects. So, I will take this investigation to improve the
tribological property of the bearing application in the future. Because the nuclear
industries are currently using the alumina ball bearings in the nuclear power plant
feed pumps.
So in this future I will planned to continue the same work to investigate
the tribological property of the nano alumina pin or ball against with SAE52100
bearing steel. Also trying to investigate the tribological property of the same
material sintered by Spark Plasma Sintering (SPS) technique. Because, this is a
conventional sintering technique to improve the physical, mechanical and
tribological property.
REFERENCES
1. Ashby, M. F., and D. R. H. Jones, “Engineering Materials 1, An Introduction to
Their Properties and Applications”, 3rd edition, Butterworth-
Heinemann,Woburn, UK, 2005.
153
2. Ashby, M. F., and D. R. H. Jones, “Engineering Materials 2, An Introduction to Microstructures”, Processing and Design, 3rd edition, Butterworth-Heinemann,Woburn, UK, 2005.
3. William D. Callister, Jr., “Fundamentals of Materials Science and Engineering”, fifth edition, John Wiley & Sons, Inc.
4. William d. Callister, jr., david g. Rethwisch, “Materials Science and Engineering an Introduction”, eighth edition, John Wiley & Sons, Inc.
5. Cowie, J. M.G., and V. Arrighi, “Polymers: Chemistry and Physics of Modern Materials”, 3rd edition, CRC Press, Boca Raton, FL, 2007.
6. Shackelford, J. F., “Introduction to Materials Science for Engineers”, 7th edition, Prentice Hall PTR,Paramus, NJ, 2009.
7. White, M. A., “Properties of Materials”, OxfordUniversity Press, New York, 1999.
8. Kingery, W. D., Bowen, H. K., and Ulhmann, D. R., "Introduction to Ceramics," 2nd ed. Wiley (Interscience), New York, 1976.
9. Levenspiel, O., "Chemical Reaction Engineering," pp. 270-300. Wiley, New York, 1972.
10. Terry A. Ring, “Fundamentals of Ceramic Powder Processing and Synthesis”, Academic Press, 1996.
11. Perttiauerkari, “Mechanical and physical properties of engineering alumina ceramics”, VTT manufacturing technology, technical research center of Finland, Espoo 1996.
12. Shinji FUJIWARA, Yasuaki TAMURA, Hajime MAKI, Norifumi AZUMA, Yoshiaki TAKEUCHI, “Development of New High-Purity Alumina”, SUMITOMO KAGAKU”, vol. 2007-I.
13. MałgorzataSopicka-Lizer, “High-energy ball milling Mechanochemical processing of nanopowders”, Woodhead Publishing Limited, 2010.
14. A. Eskandari, M. Aminzare, Z. Razavihesabi, S.H. Aboutalebi, S.K. Sadrnezhaad, “Effect of high energy ball milling on compressibility and sintering behavior of alumina nanoparticles”, Ceramics International 38 (2012) 2627–2632.
15. H. Ferkel, R.J. Hellmig, “Effect of nanopowderdeaglomeration on the densities of nanocrystalline ceramic green bodies and their sintering behavior”, Nanostruct. Mater. 11 (1999) 617–622.
16. M.A. Meyers, A. Mishra, D.J. Benson, “Mechanical properties of nanocrystalline materials”, Prog. Mater. Sci. 51 (2006) 427–556.
17. ASM Ready Reference: Thermal Properties of Metals, 2002 ASM International 18. R.E. Taylor, “CINDAS Data Series on Materials Properties, Thermal Expansion
of Solids”, Vol 1–4, ASM International, 1998. 19. “Standard Test Method for Linear Thermal Expansion of Solid Materials by
Thermomechanical Analysis,” E 831, Annual Book of ASTM Standards, ASTM, 2000.
154
ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL
ON THE MICELLATION OF SURFACTANT IN
AQUEOUS SOLUTION AT FIXED FREQUENCY 2 MHZ
AND FIXED TEMPERATURE OF 303.15K.
G. Lakshiminarayanan1 and D. Arun kumar2
1,2 Department of Physics, Shanmuga Industries Arts and Science College,
Thiruvannamalai.
ABSTRACT
Ultrasonic velocity, density and viscosity studies have been carried out in
aqueous solutions of sodium oleate and in aqueous solutions of sodium oleate
containing 5-20% V/V of methanol (ME). These studies are carried out in sodium
oleate concentration of 3mM to 12mM at a fixed frequency of 2MHz and at a fixed
temperature of 303.15K. The variation of ultrasonic velocity in aqueous solutions of
sodium oleate containing 5-20% V/V of ME sodium oleate concentration exhibiting
a break at critical micelle concentration (CMC). The ultrasonic velocity, adiabatic
compressibility, free length, free volume and internal pressure also exhibiting a
break at CMC similar to velocity curve. The results are discussed in terms of
formation of sodium oleate micelles through hydrophobic interaction and hydrogen
bonding.
INTRODUCTION
Molecular interaction in liquid mixtures has been the subject of numerous
investigation in recent past years [1-3]. The system shows a wide verity of physical
properties. Recent researchers have studied the interaction of sodium oleate (SO)
with various additive through ultrasonic techniques. But the effect of methanol on
SO is scandy. The aim our present investigation is to determine ultrasonic studies
on the effect of methanol on the micellization of sodium oleate in aqueous
solutions at fixed frequency of 2 MHz and fixed temperature of 303.15 k. The
results are interpreted in terms of formation of SO micelles in the solutions.
155
MATERIALS AND METHODS
The sodium oleate (SO) used in the present study are of AR/BDH grade
purchased from SD-fine chemicals Ltd., India and they are used as such without
further purification. The solvents used namely methanol are of spectroscopic grade.
Triply distilled deionised water is used for preparing the solutions of methanol.
Ultrasonic velocity studies are carried out at a fixed frequency of 2 MHz in the
sodium oleate concentration range of 3mM to 12mM. Ultrasonic velocity is
measured using a Digital Ultrasonic Velocity meter (Model VCT-70A, Vi-
Microsystems Pvt. Ltd., Chennai, India) at a fixed temperature at 303.15K by
circulating water from a thermostatically controlled water bath and the temperature
being maintained to an accuracy of ±0.1oC. The accuracy in measurement of
velocity and absorption is ±2 parts in 105 and 3% respectively. Shear viscosity and
density of aqueous solutions of SO containing 5-20% V/V of ME are determined
using an Oswald’s viscometer and a graduated dilatometer respectively. The
accuracy in measurement of density and viscosity is ±2 parts in 104 and ± 0.1%
respectively. From the measured values of ultrasonic velocity, density and viscosity,
the various other parameters such as adiabatic compressibility (βs), intermolecular
free length (Lf), free volume (Vf ) and internal pressure (Пi) are calculated using
standard formulae.
COMPUTATIONS OF PARAMETERS
Adiabatic compressibility (βs), intermolecular free length (Lf), free volume
(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),
respectively.
βs = 1/C2ρ (1)
Lf = KT βs 1/2 (2)
Vf = (M C / K η)3/2 (3)
πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)
where, c is ultrasonic velocity, ρ is density, KT is temperature dependant constant, M
is effective molecular weight, K is constant for liquids, b is constant, T is
temperature.
156
RESULT AND DISCUSSIONS
From the measured values of ultrasonic velocity and viscosity, the other
parameters such as adiabatic compressibility, free length, free volume and internal
pressure were computed and shown in graphically in figures (1-6).The variations of
ultrasonic velocity against concentration of sodium oleate in aqueous solution are
given in Fig 1. The measured ultrasonic velocity increases with increasing
concentration of sodium oleate in aqueous solutions and exhibits sharp break at a
particular concentration is known as Critical Micellar Concentration (CMC), which
is confirmed by G.Ravichandran et al [4]. The increase in ultrasonic velocity before
CMC is due to the oleate ions making hydrogen bond with water molecules. The
micelle formation in aqueous solution of sodium oleate and higher aggregation leads
to increase in velocity beyond CMC.
The measured ultrasonic velocity increases with increasing concentration of
sodium oleate in aqueous – alcoholic solvent (5-20%V/V of methanol) mixtures of
solution and exhibits sharp break at a particular concentration of sodium oleate
(i.e.)., CMC as shown in Fig 1. The increase in ultrasonic velocity is due to the
alcoholic solvents act as a structure breaker in aqueous sodium oleate. Sodium ions
are restricting the mobility of the water molecules. This leads to increase in
ultrasonic velocity in pre-micellar solution. The micelle formation in aqueous-
alcoholic solution of sodium oleate and higher aggregation leads to increase in
velocity for post micellar solution. In addition to average dipole moment of sodium
oleate in the solution also contributes increase in ultrasonic velocity. The velocity
observed in aqueous-alcoholic solvent at particular compositions (volume by
volume) in the order:
Velocity of 5% ME mixture < Velocity of 10 % ME mixture < Velocity of 15 % ME
mixture <Velocity of 20 % ME mixture
From the figure 1, it is observed that when the 5% V/V of methanol is added
to the aqueous solution of sodium oleate, the CMC of aqueous solution of sodium
oleate shifted towards the higher concentration side (6.5 mM). This is due to the
lowering of the average dielectric constant of the medium because of the dielectric
constant of water is greater than methanol.
157
Similarly, when the 10-20% V/V of methanol is added to the aqueous solution
of sodium oleate the CMC of aqueous solution of sodium oleate shifted towards the
higher concentration side in the order of (7.0 mM), (8.0 mM), (8.5 mM),
respectively.
Adiabatic compressibility, free length and free volume, internal pressure
studies supports the ultrasonic velocity studies in aqueous and aqueous alcoholic
solvents mixtures.
CONCLUSION
In the present study, the ultrasonic velocity, density, viscosity and internal
pressure increases whereas adiabatic compressibility, free length and free volume
decreases with increasing concentration of sodium oleate in aqueous and aqueous –
alcoholic mixture (Methanol).
The CMC value obtained in with aqueous with 20 % V/V alcoholic solvent
(Methanol) mixture is greater than all other compositions of alcohols concentrations
of sodium oleate solutions. This is due to the higher breaking nature of alcohol in
higher compositions.
0.002 0.004 0.006 0.008 0.010 0.012
1565
1570
1575
1580
1585
1590
1595
Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO
Ultr
ason
ic V
eloc
ity (m
s-1)
Molar Concentration of Sodium Oleate
0.002 0.004 0.006 0.008 0.010 0.012
8.0
8.5
9.0
9.5
10.0
10.5
11.0
Visc
osity
10-4
NSm
-2
Molar Concentration of Sodium Oleate
Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO
Figure-1 Figure-2
158
0.002 0.004 0.006 0.008 0.010 0.0124.17
4.18
4.19
4.20
4.21
4.22
4.23
Free
Len
gth
L f x 1
0-10 m
Molar Concentration of Sodium Oleate
Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO
0.002 0.004 0.006 0.008 0.010 0.0124.04
4.06
4.08
4.10
4.12
4.14
4.16
Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO
Adi
abat
ic C
ompr
essi
bilit
y( b
s )X10
-10 N
-1m
2
Molar concentration of Sodium Oleate
0.002 0.004 0.006 0.008 0.010 0.0123.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
Free
vol
ume
(Vf) m
3
Molar Concentration of Sodium Oleate
Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO
0.002 0.004 0.006 0.008 0.010 0.0122.90
2.95
3.00
3.05
3.10
3.15
3.20
3.25
3.30
3.35
3.40
Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO
Inte
rnal
Pre
ssur
e (p
i) pa
scal
Molar Concentration of Sodium Oleate
Figure-3 Figure-4
Figure-5 Figure-6
References
1. Bhattarai A, Chatterjee SK, Deo TK, Niraula TP (2011) Effects of concentration, temperature, and solvent composition on the partial molar volumes of sodium lauryl sulfate in methanol (1) + water (2) mixed solvent media. J Chem Eng Data 56:3400–3405
2. Nain AK, et al. Molecular interactions in binary mixtures of formamide with 1 butanol, 2 butanol, 1,3butaneol at different temperatures. Journal of Fluid Phase Equilibria, 2008; 265(1-2):46-56.
3. Bhoj Bhadur Gurung, Mahendra Nath Roy, Study of densities, viscosities and ultrasonic speeds of binary mixtures containing 1, 2 diethoxy ethane with alkane 1-ol at 298.15 K. Journal of Solution Chemistry. 2006; 35:1587-1606.
4. G.Ravichandran, G.rajarajan, T.K. Nambinarayanan, Journal of Molecular Liquids 267-276, 102 (2003).
159
NMR , NBO, AND VIBRATIONAL SPECTROSCOPIC ANALYSIS OF
O-NITROBENZAMIDE
D.Nandha kumara, P.Manib
aDepartment of Chemistry, Sanghamam college of arts and science,
Annamangalam,Gingee – 604210. bDepartment of physics, Shanmuga industries Atrs and science
College,Thiruvannamalai – 606603.
ABSTRACT
In the present methodical study, FT-IR, FT-Raman and NMR spectra of
o-nitrobenzamide are recorded and fundamental vibrational frequencies are tabulated
assigned. The vibrational wavenumbers were computed using HF and DFT methods.
The assigned with potential energy distribution method. Gaussian hybrid
computational calculations are carried out using HF and DFT (B3LYP and B3PW91)
methods with 6-31+G (d,p), cc-pVDZ and aug-cc-pVDZ basis sets. Moreover, 1H
and 13C NMR spectra have been analysed 1H and 13C nuclear magnetic resonance
chemical shifts are calculated using the gauge independent atomic orbital (GIAO)
method. A study on the electronic and optical properties (absorption wavelengths,
excitation energy, and dipole moment frontier molecular orbital energies) is
performed using HF and DFT methods. Stability of the molecule arising from hyper
conjugative interactions, charge delocalization has been analysed using natural bond
orbital (NBO) analysis.
Keywords: o-nitrobenzamide; gauge-independent atomic orbital; chemical shifts;
Introduction
O-nitrobenzamide is an organic compound, which consists of nitro; carbonyl
and amide groups are attached to the phenyl ring. It reacts with azo and diazo
compounds to generate toxic gases. Flammable gases are formed by the reaction of
O-nitrobenzamide with strong reducing agents. O-nitrobenzamide is very weak
bases.It is a stable compound and does not undergo polymerization. O-
nitrobenzamide is easily oxidized by using Strong oxidizing agents. Exposure to air
or moisture over prolonged periods destroys the nature of the amide.
160
The IUPAC namLe of O-nitrobenzamide is 2-Nitrobenzamide. The molecular
formula of O-nitrobenzamide is C7H6N2O3 and the molecular weight is 166.13. It is a
kind of beige crystalline powder and belongs to the classes of Aromatic Carboxylic
Acids, Amides, Anilides and Carbonyl Compounds; Organic Building Blocks. Other
synonyms of o-nitrobenzamide: 2-Nitrophenylformamide;benzamide, o-
nitro-;2-Carbamoylnitrobenzene.
2. Computational methods
In the present work, HF and some of the hybrid methods, B3LYP and B3PW91,
are carried out using the basis sets 6-31+G (d,p) and cc-pVDZ & aug-cc-pVDZ. All
these calculations are performed using the GAUSSIAN 09W [3] program package on
an i7 processor in a personal computer. In DFT methods, B3LYP is the combination
of Becke’s three-parameter hybrid function, and the Lee–Yang–Parr correlation
function [4, 5]. B3PW91 is the combination of Becke’s three parameter exact
exchange-function (B3) [6] and Perdew-Wang (PW91) correlation function [7, 8]. The
optimized molecular structure of the molecule is obtained using the Gaussian 09 and
Gaussview program and is shown in Fig. 1. The comparative optimized structural
parameters such as bond length, bond angle and dihedral angle are presented in
Table 1. The observed (FT-IR and FT-Raman) and calculated vibrational frequencies
and vibrational assignments are presented in Table 3. Experimental and simulated
spectra of IR and Raman are presented in Fig. 2 and 3, respectively.
The 1H and 13C NMR isotropic shielding are calculated using the GIAO method
[9] and the optimized parameters obtained from the B3LYP/cc-pVDZ method. 13C
isotropic magnetic shielding (IMS) of any X carbon atoms is made according to the 13C IMS value of TMS, CSX = IMSTMS-IMSx. The 1H and 13C isotropic chemical
shifts of TMS (Tetramethylsilane) in gas, DMSO, methanol and ethanol are
calculated using IEFPCM method with the B3LYP functional at the cc-pVDZ level.
The absolute chemical shift is found between the isotropic peaks and the peaks of
TMS [10]. Stability of the molecule arising from hyper conjugative interactions,
charge delocalization is analyzed using natural bond orbital (NBO) analysis.
161
4. Results and discussion
4.1. Molecular geometry
FroUm the optimized output file of Gaussian it is observed that the molecular
structure of o-nitrobenzamide belongs to C1 point group symmetry. The optimized
structure of the molecule is obtained from the Gaussian 09 and Gauss view program
[13] and is shown in Fig. 1. The present molecule contains one nitro group and one
amide group, which are loaded in the left moiety. The hexagonal structure of the
benzene is deformed at the point of substitution due to the addition of the heavy
mass. It is also evident that the bond length (C1-C2 & C2-C3) at the point of
substitution is 0.0054 Å, which is longer than the rest in the ring. Consequently, the
property of the same also changed with respect to the ligand (nitro and amide
groups). The bond angle of C1–C2–C3 is 2.0151º elevated than C4–C5–C6 in the
ring, which also confirms the deformation of the hexagonal shield. Although both
C=O and NH2 groups, the bond length values between C2–C3 and C3–C11 differed
by 0.121 Å. The entire C–H bonds in the chain and the amide groups have almost
equal inter-nuclear distance.
Figure 1: Molecular structure of O-Nitrobenzamide
4.2. Vibrational assignments
In order to obtain the spectroscopic significance of o-nitrobenzamide, the
computational calculations are performed using frequency analysis. The molecule
has C1 point group symmetry, consists of 18 atoms, so it has 48 normal vibrational
modes. On the basis of C1 symmetry, the 48 fundamental vibrations of the molecule
can be distributed as 36 in-plane vibrations of A species and 12 out-of-plane
162
vibrations of A species, i.e., vib = 36 A + 12 A. In the C1 group, the symmetry of
the molecule is a non-planar structure and has 48 vibrational modes that span in the
irreducible representations.
The vibrational frequencies (unscaled and scaled) calculated at HF, B3LYP and
B3PW91methods with 6-311+G(d,p), cc-pVDZ and aug cc-pVDZ basic sets and
observed FT-IR and FT-Raman frequencies for various modes of vibrations have
been presented in Tables 2 and 3. The Frequencies calculated at the HF and
B3LYP/B3PW91 methods are found to be high compared to experimental vibrations.
The Inclusion of electron correlation in the density functional theory to a certain
extent makes the frequency values smaller in comparjison with the HF frequency
data.
The calculated frequencies are scaled down to give up the rational with the
observed frequencies. The scaling factors are 0.8889, 0.9390, 0.9999 and 0.9909 for
HF/6-31+G (d, p). For the B3LYP/cc-pVDZ/aug-cc-pVDZ basis set, the scaling
factors are 0.9544, 1.0174, 1.0919 and 1.0881/0.9578, 1.0207, 1.0976 and 1.0929.
For the B3PW91/ cc-pVDZ/aug-cc-pVDZ basis set, the scaling factors are 0.9466,
1.0105, 1.0939 and 1.0871/0.9511, 1.0125, 1.0968 and 1.0921.
4.2.1. N H, N=O vibrations
In heterocyclic molecules, the N H stretching vibrations have been measured
in region 3500–3000 cm–1 [14]. As seen in Table 2, the two N H stretching modes are
calculated at 3494 and 3372 cm–1 in B3LYP. A very strong FT-IR N H stretching
vibration is observed at 3390 cm–1 in the experimental spectrum. Ten et al. [15] have
observed these modes at 3479 and 3432 cm–1, respectively, for isolated thymine. In
2-amino-4-methylbenzothiazole, V. Arjunan et al [16]. have observed the vibrational
frequencies at 3417 and 3287 cm−1. Cirak and Koc [17] have calculated the N–H
stretching modes at 3189 and 3155 cm−1 for dimeric trifluorothymine. However, no
Raman band is observed for the N H stretching modes in the experimental spectra.
For primary amino group the in-plane –NH2 deformation vibration occur in the short
163
range 1650–1580 cm−1 region of the spectrum. Therefore the very weak band
observed in IR at 1570 cm−1 is assigned to the deformation mode of the amino group.
The most characteristic bands in the spectra of nitro compounds are due to
NO2 stretching vibrations, which are the most useful group wavenumbers, not only
because of their spectral position but also for their strong intensity [18]. The N=O
stretching vibrations have been measured in region 1515-1560 cm–1. A weak IR
N O stretching vibration is observed at 1430 cm–1. However, no Raman band is
observed for the N=O stretching modes. Hence these vibrations show good
agreement with the literature values.
4.2.2. C–H Vibrations
The C–H stretching vibrations are normally observed in the region 3100-3000
cm−1 for the aromatic benzene structure, [19–20] which shows their uniqueness of the
skeletal vibrations. The bands appeared at 3100, 3090, 3080, and 3050 cm−1 in o-
nitrobenzamide are assigned to C–H ring stretching vibrations. The FT-IR bands at
1520 and 1470 cm−1 are assigned to C–H in-plane bending vibrations and FT-IR
bands at 860 cm−1 are assigned to C–H out-of-plane bending vibration. V.
Karunakaran et al. [21] in the molecule 4-chloro-3-nitrobenzaldehyde (CNB) have
observed the bands at 3053, 3034 cm−1 in FT-IR and at 3079, 3052 cm−1 in FT-
Raman spectra. The FT-IR bands at 1467, 1422 cm−1 and the FT-Raman bands at
1423 and 1218 cm−1 were assigned to C–H in-plane bending vibration of CNB. The
C–H out-of-plane bending vibrations of the CNB were well identified at 989, 822
and 722 cm−1 in the FT-IR and 828 cm−1 in the FT-Raman spectra V. Arjunan et al.
[22] in 4-acetyl benzonitrile, have been observed the C–H stretching peaks in IR at
3075 and 3030 cm−1 and in Raman spectrum at 3090, 3074 and 3025 cm−1. The
frequencies calculated for the present compound using B3LYP/cc-pVDZ and
B3LYP/aug cc-pVDZ methods for C–H in-plane bending vibrations showed
excellent agreement with the recorded spectrum as well as literature data.
4.2.3. C–C vibrations
V. Arjunan et al [23] in 4-acetyl benzonitrile, have observed the C–C
stretching vibrations at 1593, 1556, 1485, 1415, and 1259 cm−1 in IR spectrum and
1603, 1482, 1430, 1408 and 1270 cm−1 in Raman spectrum. The IR bands observed
164
at 1593 and 1285 cm−1 were strong while the Raman band 1603 cm−1 was very
strong. In addition, C–C–C in–plane bending vibrations have been attributed to 1002
and 844 cm−1 in IR spectrum and 794 cm−1 in Raman spectrum. The C–C–C out of
plane vibrations have observed at 337, 227 and 108 cm−1 in Raman spectrum. V.
Karunakaran et al.[24] in the molecule 4-chloro-3-nitrobenzaldehyde have observed
the C–C stretching vibrations at 1589, 1356, 1200 and 1056 cm−1 in FT-IR spectrum
and at 1626, 1372, 1160 and 1058 cm−1 in Raman spectrum.
The bands due to the C–C stretching vibrations are called skeletal vibrations
normally observed in the region 1430–1650 cm1 for the aromatic ring
compounds.[25, 26] Socrates [27] mentioned that the presence of a conjugate substituent
such as C=C causes stretching of peaks around the region of 1625–1575 cm1. As
predicted in the earlier references, in this title compound, the prominent peaks are
found with strong and medium intensity at 1600 and 1590 cm1 due to C=C
stretching vibrations. The C–C stretching vibrations are appeared at 1580, 1520,
1470 and 1400 cm1. The C-C out-of-plane bending vibrations are appeared at 1130,
1090, 1000 and 970 cm1.
4.2.4. C N vibrations
The C N vibration of the compound identification is a very difficult task,
since the mixing of several bands is possible in the region. Silverstein et al. [28]
assigned C N stretching absorption in the region 1382–1266 cm–1 for aromatic
amines. In benzamide the band observed at 1368 cm–1 is assigned due to C N
stretching [29]. However with the help of force field calculations, the C N vibrations
are identified and assigned in this study. A. Prabakaran et al.[30] in 7-(1,3-
dioxolan-2-ylmethyl)-1,3-dimethylpurine-2,6-dione (7DDMP26D) have observed C–
N, C=N stretching vibrations at 1478.19 and 1280.19 cm–1 in FT-IR spectrum and at
1480.00 and 1280.53 cm–1 in FT-Raman spectrum respectively. In our present work,
C N stretching vibrations are observed at 1400 and 1180 cm–1 in FT-IR spectrum.
This band has been calculated at 1403 cm–1 by DFT method and at 1180 cm–1 by HF
method are very good agreement with experimental values.
165
4.2.5. C=O vibrations
The C=O stretching frequency appears strongly in the IR spectrum in the
range 1600–1850 cm–1 because of its large change in dipole moment. The carbonyl
group vibrations give rise to characteristics bands in vibration spectra and its
characteristic frequency used to study a wide range of compounds. The intensity of
these bands can increase owing to conjugation or formation of hydrogen bonds [31].
Carthigayan et al. [32] have observed the bands at 1822 and 1842 cm–1 in the infrared
spectrum corresponds to C=O stretching in 4,5-Bis(bromomethyl)-
1,3-dioxol-2-one (45BMDO). The corresponding frequency of 4-Bromomethyl-5-
methyl-1, 3-dioxol-2-one (4BMDO) was observed at 1820 cm–1. A very strong IR
absorption band at 1680 cm–1 is readily assigned to the carbonyl vibration in the o-
nitrobenzamide; the corresponding DFT computed mode at 1720 cm–1 at B3LYP/cc-
pVDZ, level is good agreement with the observed one.
4.3. NBO analysis
The second order perturbation NBO Fock matrix was carried out to evaluate
the donor–acceptor interactions in the NBO analysis. The interaction result is a loss
of occupancy from the localized NBO of the idealized Lewis structure into an empty
non-Lewis orbital. For each donor (i), and acceptor (j), the stabilization energy E(2)
associated with the delocalization i j is estimated as
Natural bond orbital analysis provides an efficient method for studying intra
and intermolecular bonding and interaction among bonds, and also provides a
convenient basis for investigating charge transfer or conjugative interaction in
molecular systems [33].The intra molecular hyper conjugative interactions of π (C1–
C2) to π* (N16–O17) leads to highest stabilization of 24.54 kcal mol-1. In case of π
(C1–C2) orbital the π*(C3–C4) shows the stabilization energy of 21.84 and 17.61
kcal mol-1. Similarly in the case of π (C3–C4) to π* (C1–C2) and π* (C5–C6) anti-
bonding orbital leads to stabilization energy of 20.80 and 21.38 kcal mol-1 and from
π (C5–C6) to π* (C1–C2), π*(C3–C4) has stabilization energies of 23.46 and 19.18
166
kcal mol-1, respectively are listed in Table 4. The π – π* transition and corresponding
perturbation energy are shown in figure 4.
4.4. NMR assessment
NMR spectroscopy is currently used for the structural elucidation of complex
molecules. The combined use of experimental and computational tools offers a
powerful gadget to interpret and predict the structure of bulky molecules. The
optimized structure of o-nitrobenzamide is used to obtain the NMR spectra
supported by the GIAO method with B3LYP functional at the cc-pVDZ basic set,
and the chemical shifts of the compound are reported in ppm relative to TMS for 1H
and 13C NMR spectra, which are presented in Table 5. The corresponding spectrum
is shown in Fig. 5 & 6. 13C NMR chemical shifts for similar organic molecules usually are >100 ppm .
The accuracy ensures reliable interpretation of spectroscopic parameters. In the case
of o-nitrobenzamide, the chemical shifts of C1, C2, C3, C4, C5, C6, and C11 are
132.429, 144.929, 122.479, 120.791, 118.984, 122.882 and 179.985 ppm
respectively. The shift is higher in C2 and C11 than the others.
All the carbon atoms in the molecule are found to have higher chemical shifts it
is because of presence of highly negative atoms attached to the carbons. Among this
C11 atom has higher chemical shift compared to all other atoms. It is due to
attachment of electrons withdrawal amide carbonyl functional group.
The calculated values are compared with the experimental values. It is found that
the calculated values are higher than the experimental values. And the lower peaks of
hydrogen in experimental spectrum is found missing.
5. Conclusion
In the geometrical study, it is observed by the calculation of the bond length
and bond angle, the hexagonal structure of the compound is deformed. In the
vibrational study though most of the vibrations are in line with the literature some
the mode carbonyl group is shifted to the end position of the range. The NMR
reveals that the C11 atom which is attached to the carbonyl and amine group has
167
more shift compared all other atoms in the compound; it means that atom is more
deshielded by its electrons.
References
[1] R.J. Knox, M.P. Boland, F. Friedlos, B. Coles, C. Southan, J.J. Roberts,
Biochemical Pharmacology, 37 (1988) 4671–4677.
[2] A. Chandor, S. Dijols, B. Ramassamy, Y. Frapart, D. Mansuy, D. Stuehr, N.
Helsby, Chemical Research Toxicology, (2008), 21, 836–843.
[3] R.J. Lewis, Sr (Ed.). Hawley's Condensed Chemical Dictionary, 12th ed. New
York, NY: Van Nostrand Rheinhold Co., (1993) 860.
[4] D. Hartley and H. Kidd (eds.), The Agrochemicals Handbook. Old Woking,
Surrey, United Kingdom: Royal Society of Chemistry/Unwin Brothers Ltd.,
(1983).
[5] W. Gerhartz, Ullmann's Encyclopedia of Industrial Chemistry. 5th ed:
Deerfield Beach, FL: VCH Publishers, 1985.
[6] M.K. Marchewka, A. Pietraszko, Spectrochimica Acta Part A, 69 (2008) 312–
318.
[7] M.J. Frisch, Gaussian 09, Revision A.02, Gaussian, Inc., Wallingford CT,
2009.
[8] Z. Zhengyu, D. Dongmei, Journal of Molecular Structure, 505 (2000) 247-
252.
[9] Z. Zhengyu, F. Aiping, D. Dongmei, Journal of Quantum Chemistry, 78
(2000)186-189.
[10] A.D. Becke, Physics Review A, 38 (1988) 3098-3101.
[11] C. Lee, W. Yang, R.G. Parr, Physics Review B, 37 (1988) 785-790.
[12] A.D. Becke, Journal of Chemical Physics, 98 (1993) 5648-5652.
[13] R.L. Peesole, L.D. Shield, I.C. McWilliam, Modern Methods of Chemical
Analysis, Wiley, New York, 1976.
[14] S. Mohan, N. Sundaraganesan, J. Mink, Spectrochim. Acta A, 47 (1991)
1111–1115.
168
[15] G.N. Ten, V.V. Nechaev, A.N. Pankratov, V.I. Berezin, V.I. Baranov, Journal of Structural Chemistry, 51 (2010) 854–861.
[16] V. Arjunan, S. Sakiladevi, T. Rani, C.V. Mythili, S. Mohan, Spectrochimica Acta Part A, 88 (2012) 220–231
[17] C. Cırak, N. Koc, Journal of Molecular Modeling, 18 (2012) 4453–4464.
[18] N.P.C. Roeges, A Guide to the Complete Interpretation of Infrared Spectra of Organic Structure, Wiley, New York, USA, 1994.
[19] Y.R. Sharma, Elementary Organic Spectroscopy, Principles and Chemical Applications, S.Chande & Company Ltd., New Delhi, 1994.
[20] P.S. Kalsi, Spectroscopy of Organic Compounds, Wiley Eastern Limited, New Delhi, 1993.
[21] V. Karunakaran, V. Balachandran, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 98 (2012) 229–239.
[22] V. Arjunan, K. Carthigayan, S. Periandy, K. Balamurugan, S. Mohan, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 98 (2012) 156–169.
[23] V. Arjunan, K. Carthigayan, S. Periandy, K. Balamurugan, S. Mohan, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 98 (2012) 156–169.
[24] V. Karunakaran, V. Balachandran, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 98 (2012) 229–239.
[25] M. Silverstein, G. Clayton Basseler, C. Morrill, Spectrometric identification of organic Compounds, John Wiley, New York, 1991.
[26] C. Brian Smith, Infrared Spectral Interpretation, CRC Press, New York, 1999. [27] G. Socrates, Infrared and Raman Characteristics Group Frequencies, Wiley,
New York, 2000. [28] M. Silverstein, G. Clayton Basseler, C. Morill, Spectrometric Identification
of Organic Compound, Wiley, New York, 1981. [29] R. Shanmugam, D. Sathyanarayana, Spectrochim. Acta A, 40 (1984) 764. [30] A. Prabakaran, S. Muthu, Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy, 118 (2014) 578–588. [31] R. Zhang, X. Li, X. Zhang, Frontiers of Chemistry in China, 6 (2011) 358-366. [32] K. Carthigayan, V. Arjunan, R. Anitha, S. Periandy, S. Mohan, Journal of
Molecular Structure, 1056 (2014) 38–51. [33] S. Subhashandrabose, R. Akhil, R. Krishnan, H. Saleem, R. Parameswari,
N. Sundaraganesan, V. Thanikachalam, G. Manikandan, Spectrochim. Acta, 77A (2010) 877–884.
[34] J.N. Liu, Z.R. Chen, S.F. Yuan, Journal of Zhejiang University-Science B, 6 (2005).
169
Effect of annealing process on structural, morphological, electrical and
optical properties of CeO2 nanoparticles synthesized by Chemical precipitation
method
K. Mohanraj1, D. Balasubramanian*1, N. Jhansi1, R. Suresh2, C. Sudhakar3 1Raman Research Laboratory, PG & Research Department of Physics, Government
Arts College, Tiruvannamalai-606603 2Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and
Science, Coimbatore- 20 3PG & Research department of Chemistry, Government Arts College,
Tiruvannamalai-606603
Corresponding author: [email protected] Mobile: +91 9677971999
Abstract
Cerium oxide nanoparticles are successfully synthesized by Chemical
precipitation method. Effect of annealing process on the crystallite growth of cerium
oxide nanoparticles properties are investigated by various XRD, SEM, PL and I–V
studies. Crystallites are detected by X-ray diffraction pattern with preferred
orientation along (111) direction. Annealing temperature affects the crystallinity and
structural parameters like grain size, texture coefficient, and dislocation density. PL
spectra revealed that strong and broad emission band is observed at 425 nm due to
the presence of blue shift in the visible region. Large agglomerated spheroid
crystallites are obtained with the typical size in the range 4–12 nm.
Keywords: Cerium oxide nanoparticles, Structural, Morphological, Optical
properties.
1. Introduction
Nanomaterials contain particles with one dimension in the nanometer regime.
Now days, there is a growing interest from the scientific community in the
applications of these nanomaterials which is sometimes referred to as “the next
industrial revolution” [1]. Nanoparticles have received much attention in the field of
material science because of their fascinating mechanical and physic chemical
properties which are entirely different from their bulk counterparts. Semiconductor
170
nanoparticles are of great interest due to their electronic and optical properties [2].
Among these semiconductor nanoparticles, cerium oxide has been of great interest in
versatile applications due to its chemical stability and close lattice parameter with
silicon [3]. It is a noticeable functional material with an extraordinary capacity to
store and release oxygen with cubic fluorite structure [4]. Among oxides, the cubic
CeO2 phase (fluorite) has long been considered as one of the most promising
materials because of high refractive index, good transmission in visible and infrared
regions, strong adhesion, and high stability against mechanical abrasion, chemical
attack and high temperatures [5]. Several methods have been adopted for the
preparation of ultrafine ceria nanoparticles including Co-precipitation, hydrothermal,
pyrolysis, reverse micelles, sol–gel, sonochemical, solvothermal and simple
precipitation method. Among these methods, ammonia precipitation method is
widely adopted in laboratories because of its low preparation cost and simple
process.
It has fascinated substantial attention of researchers because of its wide band
gap and considered as a promising material for automobile exhaust, buffer layers,
catalyst, filters, gas sensors, solid oxide fuel cells (SOFC).
In the present work, the crystallographic structures, surface morphology,
optical properties and I–V characteristics as a function of annealing temperatures
prepared by chemical precipitation method using cerium nitrate as the source
material are investigated and presented.
2. Experimental details
Cerium oxide (CeO2) nanoparticles are prepared using cerium nitrate and
aqueous ammonia purchased from HIMEDIA, Mumbai. In the process of synthesis,
0.1 M of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) is dissolved in 50 ml of
deionized water and strongly stirred for 30 min, then 25 ml of aqueous ammonia
solution is added dropwise to the above solution for 20 min and stirred for 10 h at
room temperature. Interesting changes appeared in color of the solution when
precipitant was added to cerium nitrate solution.
Initially at low pH slurry is light brown, possibly due to Ce3+, which is turned
into light white–black in 2 h, then turned into brown after 3 h, then light or orange
for 5 h, finally light yellow due to the formation of Ce4+ in the presence of oxygen.
171
The obtained slurry is filtered and washed several times with deionized water and
ethanol. The washed precipitate is dried in oven at 60 C for 3 h. The dried powders
are well grinded for 15 min using mortar pestle and annealed to 450 and 900 C for 2
h to enhance the crystallinity of the samples. The synthesis mechanisms may be
described by the following reactions.
Ce(NO3)3 · 6H2O + 2NH4OH CeO2+ 2NH4(NO3) +NO2 +7H2O450-900 oC
A precipitate is obtained by adding solution to NH4OH. The formation of
cerium hydroxide after oxidation of Ce3+ to Ce4+ at high pH is obtained and then
cerium hydroxide is converted into cerium oxide with the removal of hydroxyl
group.
3. Results and discussion
3.1 X-ray diffraction analysis
172
Figure 3.1 XRD patterns of CeO2 nanoparticles
Table 1. Structural Properties of Cerium Oxide nanoparticles
Sample
name
2 Theta
(Degree)
FWHM
( Å) hkl
Crystallite
Size (nm)
Dislocation
Density Strain
Stacking
Fault
Texture
Coefficient
Lattice
Constant
(Å)
as-
prepared
28.3847
33.1036
47.4956
59.1285
69.2523
0.7144
0.6494
0.4546
0.7793
0.9504
1 1 1
2 0 0
2 2 0
2 2 2
4 0 0
11.9
13.3
19.9
12.2
10.6
7.24
5.06
1.60
3.47
4.00
3.15
2.43
1.15
1.53
1.53
0.3594
0.3013
0.1733
0.2617
0.2893
1.14306
1.10495
1.09601
0.67445
0.98159
5.446
5.412
5.412
5.412
5.422
Annealed
450oC
28.4372
33.2547
47.6549
0.2273
0.7144
0.7144
1 1 1
2 0 0
2 2 0
37.6
12.0
12.6
0.73
6.34
3.95
1.00
2.75
1.80
0.1142
0.3307
0.2719
1.16917
0.99964
1.06889
1.08844
5.436
5.389
5.384
173
Crystal structure and phase identification of the samples are analyzed from
the X-ray diffraction pattern. XRD pattern of Cerium oxide powders confirmed the
presence of cubic fluorite structure with preferred orientation along (111) direction
as shown in Fig. 4.1 a-c. All Bragg peaks with miller indices (111), (200), (220),
(311), (222), (400), (331) and (420) are associated with the cubic lattice of pure
CeO2 and is in good agreement with JCPDS DATA (34-0394). No identifiable
diffraction peaks are observed for the evidence of Ce2O3 crystallite phase in XRD
pattern and it shows the single phase nature of ceria nanoparticles. The XRD pattern
of annealed samples shows the increased intensity with decreased FWHM which
confirms the improved crystallinity. The annealing temperature strongly affects the
structural parameters like crystallite size and lattice constant as shown in Fig.3.2 a-c
and table 1. Annealing temperature increases the crystallite size from 11.9 nm to
52.7 nm. It must be noted that the crystallite size increases gradually with increasing
annealing temperature and crystal growth becomes sharp at temperature above
56.2610
59.1246
69.4298
76.7669
0.3897
0.7793
0.7793
0.792
3 1 1
2 2 2
4 0 0
3 3 1
24.1
12.2
12.9
13.3
0.93
3.47
2.68
2.31
0.81
1.53
1.25
1.11
0.1348
0.2617
0.2368
0.2251
0.92511
0.90611
0.84264
5.424
5.412
5.418
5.407
Annealed
900 oC
28.6819
33.2149
47.5863
56.4383
59.1787
69.5008
76.7904
79.1576
0.1624
0.1624
0.1624
0.1584
0.1188
0.1584
0.1584
0.1188
1 1 1
2 0 0
2 2 0
3 1 1
2 2 2
4 0 0
3 3 1
4 2 0
52.7
53.3
55.8
59.4
80.2
63.7
66.8
90.5
0.37
0.32
0.20
0.15
0.08
0.11
0.09
0.05
0.71
0.61
0.41
0.33
0.23
0.25
0.22
0.16
0.0812
0.0752
0.0618
0.0547
0.0398
0.0481
0.0450
0.0330
1.17205
1.05875
1.05011
0.93234
0.85124
0.83948
0.99289
1.10319
5.390
5.394
5.404
5.403
5.404
5.405
5.406
5.406
174
500oC, it may be assumed that the particles grow mainly as a result of an interfacial
reaction. The lattice constant of the samples are slightly higher compare to the bulk
counter parts due to its increased oxygen vacancies. The influence of particle size on
lattice parameter also noticed from XRD pattern.
The particle size increases, the value of lattice parameter decreases as shown
in Fig. 3.2a. The texture coefficient clearly indicates that the samples are highly
oriented in (111) direction. Straight line of ln (D) vs 1/T is plotted in Fig. 3.2d
according to the Scott equation, given below on the assumption that the
nanocrystallite growth is homogeneous, which approximately describes the
nanocrystallite growth during annealing ,
where, D is the crystalline size, C is the constant, E is the activation energy
for nanocrystallite growth, R is the ideal gas constant and T is the absolute
temperature of heat treatment. The activation energy of CeO2 nanoparticles during
annealing is found to be 1.004 eV.
Figure 3.2 Structural parameters of CeO2 nanoparticles
)1(exp
RTECD
175
Figure 3.3 SEM images of CeO2 nanoparticles
3.2 SEM Analysis
Fig. 3.3a shows the photograph of the as-prepared sample. SEM images of
as-prepared sample show the agglomeration of small crystallites and are attributed to
uncontrolled coagulation during precipitation at higher temperature. Small
crystallites are clinging together to form a large agglomerated spheroidal structure.
Annealing temperature improves particle size from 10 to 50 nm due to compact of
small granules joined together to form agglomeration of large granules as shown in
Fig.3.3 b-d in accordance with XRD results.
3.3 PL studies
RTPL spectra of Cerium oxide nanoparticles measured using 325 nm
excitation wavelength is shown in Fig. 3.4a-c. It exhibits strong blue emission with a
photoluminescence peak at 425 nm and relative weak green emission bands at 466
nm. The investigation showed that the emission bands ranging from 400-500 nm for
cerium oxide samples are attributed to the hopping from different levels of the range
from Ce 4f and O 2p band. The strong emission of the Cerium oxide samples at 466
nm is related to the abundant defects like dislocations, which are helpful for fast
oxygen transportation [9]. The defects energy levels between Ce 4f and O 2p are
dependent on the temperature and density of defects in the crystal. The annealed
(a (b
(c (d
176
samples show the strong and sharp emission bands at 425 nm in the blue visible
region.
Fig. 3.4 PL spectra of CeO2 nanoparticles
3.4 Electrical Properties
The Electrical conductivity of the prepared samples are calculted from the
following equation,
)2(/
CmS
Alx
VI
Where, I is the Current, V is the Applied Voltage, l is the thickness and A is
the Cross sectional area of the sample. In order to investigate the rectifying behavior
of the samples at different temperature, I-V characteristics are obtained by
connecting Keithley electrometer to thetwo probe setup.Then the current drop across
the sample for constant voltage is measured for different temperatures 30-200 oC. At
room temperature, CeO2 is nonconductive.
As the temperature increases, it becomes conductive and the electrical
conductivity σ depends strongly on the temperature. I-V characteristics of as-
prepared samples show sharp decrease of conductivity with the increase of
temperature upto 100 oC, that may be attributed to the presence of un eavoprated
precursor solvents and then slight decreases upto 200 oC. The annealed samples
show the slight decrease of conductivity upto 160 oC and sharp increase upto
177
Figure 3.5 I-V Characteristics of CeO2 nanoparticles
200 oC as shown in Fig. 3.5a-d. The conductivity is calculated using above formula
and the values are listed in table 2. The conductivity is found to be in the range
2.76X10-7 - 8.76X10-12 S/Cm. Fig. 4.5e shows the variation of ln (ρ) with
temperature for the prepared samples. It indicates the negative temperature
dependence of resistivity for as-prepared samples, where as annealed samples
indicate the positive temperature dependence of resistivity [7]. The activation energy
(Ea) is calculated using the following resistivity relation,
)3(exp
KTEa
o
Where, ρ is the resistivity of cerium oxide nanoparticles, is the pre-
exponential factor, Ea is the activation energy, K is the Boltzmann constant and T is
the absolute temperature. The activation energy values for cerium oxide
178
nanoparticles are calculated from the slop of the Arrhenius plot over the entire
temperature range as shown in Figure. The calculated activation energy is found to
be 0.984 eV according to XRD pattern. This value is in good agreement with the
values reported earlier.
Table 2. Electrical conductivity of cerium oxide nanoparticles
Conductivity (S/Cm) Temperature
(oC) C asp (X10-7) C A450 (X 10-10) C A900 (X10-11)
30 2.76425 7.46061 2.59054
40 2.47024 3.91858 3.92332
50 2.86441 0.46858 1.25131
60 2.49581 0.16504 0.81367
70 2.07096 0.08295 0.46885
80 1.51152 0.01896 0.39679
90 1.01162 0.04982 0.3605
100 0.49832 0.10437 0.34602
110 0.42625 0.19725 0.42526
120 0.38558 0.44119 0.45333
130 0.35462 0.86374 0.51049
140 0.3299 1.67356 0.66615
150 0.30241 2.69818 0.87671
160 0.28234 4.03346 1.34181
170 0.2603 6.15395 2.19979
180 0.23497 13.5364 6.28464
190 0.22778 37.4777 12.2985
200 0.23776 94.3789 21.0725
4. Conclusion
Nanocrystalline dispersed and uniform sized cerium oxide nanoparticles are successfully synthesized by a simple chemical precipitation method. From the results obtained it has been concluded that the selected material for the study has potential are several of research. Besides, the following conclusions are obtained.
179
PL spectra reveal the presence of blue emission in the visible region. XRD pattern confirms the single phase cubic fluorite structure with preferred orientation along (111) reflection. Annealing temperature increases the crystallite size upto 50 nm at 900oC.
Influence of particle size decreases the lattice constant. SEM images show the formation of large agglomerated spheroidal structure with an average particle size 10-50 nm. Annealing temperature improves the particle size and the agglomeration.
The calculated conductivity is in the range 2.76X10-7-8.76X10-12 S/Cm. The activation is energy calculated as 0.984 eV. Based on these results, it has been concluded that the annealing temperature strongly affects the surface, structure, electrical conductivity and oxidation states of cerium oxide nanoparticles.
References
1. I.R. Larramendi, N. Ortiz-Vitoriano, B. Acebedo, D.J. Aberasturi, I.G. Muro, A. Arango, E. Rodriguez-Castellon, J.I.R. Larramendi, T. Rojo, Pr-doped ceria nanoparticles as intermediate temperature ionic conductors, International Journal of Hydrogen Energy 36 (2011) 10981–10990.
2. N.K. Renuka, Structural characteristics of quantum-size ceria nano particles synthesized via simple ammonia precipitation, Journal of Alloys and Compounds 513 (2012) 230–235.
3. S. Wang, W. Wang, J. Zuo, Y. Qian, Study of Raman spectrum of CeO2 nanometer thin films, Materials Chemistry and Physics 68 (2001) 246–248.
4. J.R. Vargas-Garcia, L. Beltran-Romero, R. Tu, T. Goto, Highly (1 0 0)-oriented CeO2 films prepared on amorphous substrates by laser chemical vapor deposition, Thin Solid Films 519 (2010) 1–4.
5. F. Zhang, S.W. Chan, J.E. Spanier, E. Apak, Q. Jin, R.D. Robinson, I.P. Herman, Cerium oxide nanoparticles: size-selective formation and structure analysis, Applied Physics Letters 80 (2002) 127–129.
6. A. Kumar, S. Babu, A.S. Karakoti, A. Schulte, S. Seal, Luminescence properties of Europium-doped cerium oxide nanoparticles: Role of vacancy and oxidation states, Langmuir 25 (2009) 10998-11007.
7. T. Ristoiu, T. Petrisor Jr., M. Gabor, S. Rada, F. Popa, L. Ciontea, T. Petrisor, Electrical properties of Ceria/carbonate composites, Journal of Alloys and Compounds 532 (2012) 109-113.
180
SYNTHESIS AND CHARACTERIZATION OF PURE AND L-ALANINE
DOPED AMMONIUM DIHYDROGEN PHOSPHATE(ADP)
R. Deepika, P. Meena* Department of Physics, PSGR Krishnammal College for Women, Coimbatore, India.
Abstract: pure and Doped (with L-alanine) Ammonium dihydrogen phosphate
(ADP) crystals were grown by slow evaporation method at room temperature. The
grown crystals were subjected to powder X–ray diffraction studies to study their
structural characteristics. addition of amino acid is found to improve the
crystalquality, yielding highly transparent crystals with well-defined features. The
values of the lattice parameters were determined by single crystal X-ray
diffractionThe vibrational frequencies of the grown crystals were identified using
FT-IR spectral analysis.The UV-visible study confirms the wide optical
transmittance window for all doped crystals which is vital for optoelectronics
applications. The transmission data has been used to evaluate the optical band gap
and optical conductivity.
Key words:ADP,AMINO ACID-L-ALANINE,FTIR,UV XRD.
1. INTRODUCTION
Ammonium dihydrogen phosphate (NH4H2PO4) crystals attract much interest
because of their unique non– linear optical, dielectric, piezoelectric and
antiferroelectric properties and their variety of uses such as electro-optic modulators,
harmonic generators and parametric generators [1-3]. Several research works have
been carried out on pure and doped ADP crystals [1-5].With an aim to find new
useful materials for academic and industrial use, an attempt has been made to modify
the ADP crystals by adding 1 mole % by weight of L-ALANINEin the mother
solution of ADP.
2. EXPERIMENTAL PROCEDURE
2.1. Crystal Growth:
Pure ADP and L-alanine (AR grade) doped ADP crystals were grown using a
good quality seed crystal at room temperature by the solvent evaporation method.
For the preparation of seed crystals, the supersaturated solution of ADP was
181
prepared first and then kept in a petri dish coveredwithperforated polyethylene to
allow the growth of seed crystals within 4 - 5 days. The purity of the crystals was
improved by successive recrystallization process. The period taken for the growth of
bigger size crystals is 25 - 30 days. The grown crystalswere found to be colorless
and transparent. The crystals were characterized using powder XRD technique, FTIR
and UV-VIS-NIR spectroscopic techniques.
2.2. CHARACTERIZATION:
The grown crystals were subjected to powder X–ray diffraction studies to
study their structural characteristics. The addition of amino acid is found to improve
the crystalquality, yielding highly transparent crystals with well-defined
features.Fourier transform infrared (FTIR) spectral analysis was performed to
identify the presence of various functional groups in the crystalsin the range of 4000-
400 cm -1.The UV–Visible–NIR spectral analysis was carried out to confirm the
improvement in the transparency of the ADP crystal on addingL-alanine. The optical
properties of the grown crystals were studied using Shimadzu UV-1601 visible
spectrometer in the wavelength region 200-1100 nm.
3. RESULT AND DISCUSSION
3.1. XRD Analysis:
The crystallographic structure and lattice parameters of the ADP single
crystalsgrown by the slowevaporation methodwere determined from the X-ray
diffraction pattern obtained employing X-ray diffractometer. The diffraction peaks of
the XRD patterns shown in Figure 2 could be indexed as those of the ADP with
tetragonal structure (JCPDS Card No.37-1479). The XRD peaks were indexed and
crystallographic lattice parameters were determined by powder-X software. The
determined lattice parameters are a = 7.502 °A and c = 7.554 °A having space group
The lattice parameters are in good agreement with the reported values. The.42ܫܫ
obtained spectrum is shown in Fig. 1. The prominent peaks of pure ADP are (101),
182
(200), (211), (220), (301) and (400).The obtained peaks for the doped(L-alanine)
crystals are similar to that of the pure ADP crystalwith a slight variation in the
intensity.X-ray powder diffraction patterns of pure ADP and doped ADP crystals are
found to be identical. As seen in the figure, no additional peaks are present in the
XRD spectra of doped ADP crystals, showing the absence of any additional phases
due to doping.
Fig. 1. Powder XRD spectra of (a) pure ADP crystal and L-alanine doped
ADP crystal
3.2. FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR):
The influence of additives used in this work on the vibration frequencies of
functional groups of pure ADP crystal has been identified by FTIR spectroscopy.The
FTIR spectra were recorded in the regions 400–4000cm−1 using a Perkin Elmer FTIR
Spectrum RXI spectrometer by the KBr pellet technique. Fig.2 shows the FTIR
spectra of Pure and L-Alanine doped ADP crystal. The functional groups of pure
ADP crystals involved in vibration frequency have been identified using FTIR
spectroscopy. The peak at 589.92 cm-1is due to the PO4-vibrations in ADP
crystal.The peaks between 613.39 and 866.08cm-1 are due to the P-O-H Vibration
and P-O-H Stretching.The peaks between 1079.22cm-1and 1090.79cm-1are also due
to the P-O-H Vibration and P-O-H Stretching.The peaks between 1220.99cm-1and
1268.25cm-1 are due to combination of the asymmetric stretching vibration of PO4
with the latticeP-O stretching vibration.The peak at 1408.10cm-1is attributed to the
Bending vibration of ammonium,and bendingand stretching of NH4.The peaks
183
between 1562.41and1747.58cm-1are due to O-H Bending vibration. The peaks
between 3002.33cm-1and 3209.69 cm-1 are due to O-H Stretchingand N-H
Vibration.These support the presence of L-Alanine in the lattice of ADP.
Fig 2.FTIR spectra of Pure and L-alanine doped ADP crystals
Table 1.1 shows the FTIR spectra of Pure and L-alanine doped ADP crystal.
Pure
ADP
Doped ADP Band assignments
3209.69-
3024.51
3002.33 O-H Stretching,
P-OH Stretching,
N-H Vibration
1562.41 1747.58-
1598.09
O-H Bending vibration,
O-H Bending water
1408.10 _ Bending vibration of
ammonium ,Bending
stretching of NH4
1268.25 1266.32-
1220.99
Combination of the
asymmetric,stretching
vibration of PO4 with
lattice,P-O stretching
vibration
1079.22 1090.79 P-O-H vibration,P-O-H
stretching
184
866.08-
663.54
613.39 P-O-H vibration,P-O-H
stretching
598.92 _ PO4 vibrations.
3.3. OPTICAL STUDIES UV-VIS-NIR SPECTROSCOPY:
Optical transmission spectra were recorded for the samples obtained from
pure as well as additive added crystals grown by the slow evaporationmethod. The
spectra were recorded in the wavelength region from 200 to 2200 nm.
The UV–Vis spectra recorded for pure and additive added ADP crystals is
shown in Fig.3It is clear from the figure that the crystals have good transmission in
the entire visible and IR region.The optical transparency of the ADP crystal is
increased by the addition of L-alanine. It has also been observed that the cut off
wavelength is the same for pure and additive added ADP crystals.The addition of the
amino acid dopants in the optimum conditions to the solution is found to suppress
the inclusions and improve the quality of the crystal with higher transparency
.
Figure 3.Transmittance spectrum of ADP single crystal and doped ADP crystal
Table .1 Band gap energy
SAMPLE DIRECT BANDGAP ENERGY
ADP 3.7ev
ADP+ L-ALANINE 3.8ev
185
Fig-4 Direct bandgap energy for ADP.
Fig-5 Direct bandgap energy for ADP+L-ALANINE
4. CONCLUSION
Good quality transparent single crystals of ammonium dihydrogen phosphate
(ADP) (NH4 H2 PO4) have been grown by the slow evaporation method at room
temperature. The X-ray diffraction pattern of ADP showed that the prepared crystals
possess tetragonal structure with lattice parameters in good agreement with the
reported data (JCPDS Card No.37-1479). The functional groups of ADP crystals
involved in vibration frequency were identified using FTIR.The optical bandgap
values determined from the optical transmittance study of the ADP crystals and
doped ADP give direct bandgap values of 3.7 eV and 3.8 eV respectively. The
addition of L-alanineis found to help the growth of high quality large size single
crystals at a faster growth rate.
REFERENCES
[1] S.R.Marder, B.G.Tiemann, J.W.Perry, et.al., Materials for Non-linear optical chemical perspectives (American Chemical Society, Washington, 1991).
[2] P.Santhana Raghavan and P.Ramaswamy, Recent Trends in Cryst. Growth (Pinsa 68, New Delhi, 2002).
[3] A.Anne Assencia and C.Mahadevan, Bull of Mater. Sci., 28, 2005, 415. [4] V.Ya.Gayvoronsky, M.A.Kopylovsky, V.O.Yatsyna, A.S.Popov,
A.v.Kosinova, I.M.Pritula, Functional Mater., 19, 2012, 54. [5] J.Zhao, M.Ikezawa, A.V.Ferderov, Y.Masumoto, J.Lumin., 525, 2000, 87.
186
Novel synthesis route of γ- glycine single crystal in the presence of
2-aminopyridine potassium chloride for optoelectronic applications
R. Srineevasan
P.G & Research Department of Physics, Government Arts
College,Tiruvannamalai,606603,India
Abstract
In this research paper, an overview of polymorph γ-form glycine single crystal
crystallization in the presence of 2-aminopyridine potassium chloride as an additive
at an anambient temperature by slow evaporation solution growth technique (SEST)
has been presented. FTIR and NMR studies confirm the presence of functional
groups in the grown crystal. In the UV–Visible NIR optical absorption spectral
studies from 200 nm to 900 nm, the observed 0% absorption with lower cutoff wave
length at 240 nm enables the calculation of band gap value. Powder XRD study
confirms crystalline nature of the grown γ-glycine crystal. The single crystal XRD
study shows that the grown crystal possesses hexagonal structure and belongs to
space group P31 with the cell parameters a=7.09 Å; b=7.09; c=5.52 Å; α = β = 90˚;
and γ = 120˚. Thermal studies have been carried out to identify the enhanced thermal
stability and decomposition temperature of the grown sample. Dielectric studies of as
grown γ-glycine crystal exhibit low dielectric constant at higher frequencies, which
is most essential parameters for nonlinear optical applications. SHG efficiency of the
grown crystal was confirmed by the Kurtz powder technique using Nd:YAG laser
and found 1.6 times greater than that of inorganic standard potassium dihydrogen
phosphate.
Keywords: Slow evaporation, Single crystal, NMR spectrum, TGA-DTA, SHG
efficiency.
1. Introduction
Highly polarizable conjugated system of organic molecule possesses
non-centro symmetry structure. The inorganic molecule (anion), linking through
hydrogen bond with organic molecule (cation) yields strong mechanical and high
thermal stability [1,2]. Molecular charge transfer induced in semiorganic complex by
delocalized π electron, such that moving between electron donor and electron
acceptor which are in opposite sides of the molecules [3,4]. In the base acid
187
interaction of organic and inorganic molecules, there is a high polarizable cation
derived from aromatic nitro systems, linked to the polarizable anion of inorganic
molecules through hydrogen bond network yields a noncentrosymmetric structural
systems and this hydrogen bonding energy between organic and inorganic molecules
made the dipole moment in parallel fashion ensures the increase of second harmonic
generation activity [5]. The structures of 2-aminopyridine complexes have already
been studied by Chao and his co-workers [6]. In recent years metal organic
complexes have been played reasonable attention in advancement of technology
[2,7]. Growth of 2-aminopyridine complex crystals is widely used in the
rapid advancement in technology, such as ultra-fast phenomena, optical
communication and optical storage devices , frequency doublers and optical
modulators [8]. Optical properties of 2-aminopyridine complexes and their suitability
for optoelectronic devices have been reported [9-14]. Metal organic nonlinear optical
crystals possess good second harmonic generation efficiency, hence rich demand in
optical storage devices, color display units and optical communication systems [7].
Recent research focus is on designing of new materials capable of attaining SHG
processes by strong interaction with an oscillating field of light. Amino acids with
ionic salt complex crystals have been investigated and recognized as materials
having good nonlinear optical properties [1,3,15-17]. In this present work, synthesis
and crystallization of glycine into γ-form glycine in the presence of aqueous solution
2-aminopyridine potassium chloride and their suitability for device fabrication with
various enhanced physical properties are reported.
2. Experimental Procedure
2.1 Material synthesis
The title compound was synthesized by taking analytical grade glycine,
2-aminopyridine and potassium chloride in the stoichiometric ratio (1:1:1) with
Millipore water of resistivity 18.2 mega-ohm.cm-1 as a solvent.
In this synthesis, protonation of nitrogen in pyridine ring facilitates hydrogen
bonding interaction between potassium chloride and glycine such that 2-
aminopyridine is linked to the metal K+ ion through pyridine ring nitrogen, rather
than amino group nitrogen leaving (Cl)- ion [18].
C5 H6 N2 + KCl + NH2 CH2 COOH → [(K+) + C5H6N2 COOCH2 NH2 (Cl)–]
188
[(2-aminopyridine) + (potassium chloride) + (glycine)]→ [(γ-glycine crystal)]
Amino group hydrogen in 2-aminopyridine coordinates through hydrogen bond
with carboxylic groups of monoprotonated glycinium ion. Stacking of γ- glycine
crystal one over the other is shown in Figure 2.1.
N
N C
H
O
C
H
H
N
H
H
N
N C
H
O
C
H
H
N
H
H
K
K
Cl
Hydrogen Bond
Figure 2.1 Scheme of as grown γ-glycine crystal
2.2 Solubility study of γ-glycine in the presence of 2-aminopyridine potassium
chloride
Solubility is an important parameter, which dictates the crystal growth
process. The solubilities of the title compound in aqueous medium were estimated in
the temperature range between 30 and 50˚C. Neither a flat nor a steep solubility
curve and less viscous solution enabling the faster transfer of the growth units by
diffusion of the title compound, enables the growth of bulk crystals from solution.
Variations in solubility at different temperatures is plotted in Figure 2.2 The
moderate variations in solubility indicate the reasonable growth rate of title
compound along all crystallographic directions.
25 30 35 40 45 50
2
4
6
8
10
12
14
16
18
20
2-APKCG
Solu
bilit
y (g
/100
ml)
Temperature ( 0C) Figure 2.2 Solubility curve of title compound at different temperatures
189
2.3 Crystal Growth
The prepared mother solution was stirred vigorously for 4h using magnetic
stirrer. High degree of purification of synthesized salt was achieved by successive
recrystallization process. Synthesized saturated solution was filtered using filter
paper of micron pore size. The filtered solution was pored in different petri dishes
and covered with porous paper for slow evaporation. After a time span of 15 days,
quality crystals of average size 13mm x 12mm x 3mm were harvested. The
as grown crystal is shown in figure2.3.
Figure 2.3 As- grown γ-glycine crystal
3. Results and discussion
The as grown γ-glycine crystal was subjected to FTIR analysis using PERKIN
ELMER SPECTRUM RX1 Fourier Transform infrared spectrometer. 1H NMR and 13C NMR spectroscopic studies were done by a Bruker Advance III 500MHz
FTNMR spectrometer using D2O as solvent to identify the functional groups. The
transmission behavior was studied by using LAMBDA-35 UV-VIS
Spectrophotometer. Single crystal and powder XRD analysis were carried out on a
PHILIPS X PERT MPD system. TGA and DTA analysis were carried out using
NETZSCA STA 409 instrument at a heating rate of 20°C min-1 from ambient to
500°C. Dielectric studies were carried out by using HIOKI 3532 HiTESTER LCR
meter. The NLO efficiency of the grown crystal was tested by KURTZ powder
technique using Nd: YAG laser of wavelength 1064 nm.
3.1 Fourier Transform Infrared (FTIR) analysis
The as grown γ-glycine crystal was subjected to FTIR analysis by KBr
pellet technique in the wavelength between 4000 and 400 cm-1. The recorded
190
absorption spectrum of title compound confirms the presence of various functional
groups and their frequency assignments are shown in figure 3.1. The doublet
frequency 928.06 and 888.46 cm-1 clearly shows the γ- glycine formation [19]. The
vibrational frequencies are assigned with structure as shown in Table 1.
Table 3.1. Frequency of the vibrations and their assignment of as grown γ-
glycine crystal
3105
.77
2887
.67
2604
.48
2360
.74
2171
.48
1586
.84
1492
.95
1393
.84
1327
.82
1126
.21
1041
.67
928.
0688
8.46
683.
10
502.
8745
2.34
412.
37
500100015002000250030003500Wavenumber cm-1
2030
4050
6070
8090
100
Tran
smitt
ance
[%]
Fig 3.1 FTIR spectrum of the grown γ-glycine crystal
Frequency in wave number
(cm-1)
Assignment of vibration
3105.77 NH3+ Stretching
2887, 2604 Aliphatic CH2 Stretching
2171.48 NH3+ Stretching
1586.84 NH2+ Bending
1492.95 COO - Symmetric Stretching
1327.82 CH2 Twisting
1126.21 NH2+Rocking
1041.67 C-N Stretching
928.06 CH2 Rocking
888.46 C-C-N Symmetric Stretching
683.10 COO - Bending
502.87 COO - Rocking
191
3.2 NMR spectrum
1H NMR and 13C NMR analysis of the as-grown γ-glycine crystal were
shown in figure 3.2 & 3.3. 1H NMR spectrum of as-grown γ-glycine crystal showed
multiple peak signals at δ 3.461 to 3.445 ppm (quartet or triplet) corresponds to
protons of methylene group (CH2) and peak at δ 4.678 ppm due to amino group
protons (NH2). 13C NMR spectrum of as-grown γ-glycine crystal showed peaks at δ
41.429 ppm and δ 172.41 ppm corresponding to methylene carbons and carbonyl
carbon respectively. All the above results support the true chemical reactions in the
formation of the γ-glycine crystal.
Figure 3.2 1H NMR of γ-glycine crystal
Figure 3.3 13C NMR of γ-glycine crystal
192
3.3 UV- Visible spectral analysis
The optical properties of the crystals are mainly depends on the interaction
between crystal and components of electric and magnetic fields of the
electromagnetic wave. UV-Visible absorption spectrum of the grown crystal
recorded in the wave length range 200-900 nm was shown in figure 3.4. The
grown crystal has good transmission (100%) in UV, Visible and IR region. This
highest transmission percentage (100%) clearly shows the intrinsic property of
amino acid and their defect less nature of the grown γ-glycine crystal [20]. The
absorption spectrum shows that the grown crystal has lower cut off wavelength at
240 nm and this characteristic is most favorable for nonlinear optical materials.
Lower cut off wavelength value of the γ-glycine crystal (240nm) is compared
with Glycine potassium chloride (GPC), Serine sodium chloride (SSC), Bis
glycine Maleate, Pure Glycine, Glycine potassium sulphate (GPS), and Glycine
picrate as shown in Table 2. This observed decreasing lower cutoff wavelength
value of the as grown crystal is due to the addition of 2-aminopyridinium
potassium chloride. Hence the lower cut off wave length of as grown crystal can
be suitably used for optoelectronic application in the UV, Visible and IR range.
Table 3.2
*present work
Crystals Name Cutoff wave
length(nm)
GPC 295
SSC 300
Bis glycine
Maleate
330
Pure Glycine 346
GPS 384
Glycine picrate 450
γ- glycine crystal* 240
193
200 300 400 500 600 700 800 900
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Abs
orba
nce
(a.u
)
Wavenumber (nm)
Figure 3.4 UV-Visible absorption spectrum of grown crystal of γ-glycine
Since optical properties of the crystals are governed by the interaction
between the crystal and the electric and magnetic fields of the electromagnetic
wave, transmittance (T) was used to calculate the absorption coefficient (α) using
the formula:
1 2 3 4 5 6 7
0
50
100
150
200
250
300
Eg=5.5 ev
(alp
ha.h
v)2 .e
v2 .mm
2
hv ev
Figure 3.5 Plot of hυ versus (αhυ)2 of as grown γ-glycine crystal
Where t is the thickness of the sample. The optical band gap (Eg) was evaluated from
the transmission spectra and the optical absorption coefficient (α) near the absorption
edge is given by [21].
αhυ=A(hυ-Eg)1/2
194
where A= constant, Eg= the optical band gap, h= the Plank’s constant and υ= the
frequency of the incident photons. The graph drawn between hυ (E=hυ) and (αhυ)2
is used to estimate the direct band gap value of the grown crystal as shown in
figure3.5. The band gap of γ-glycine single crystal was estimated by extrapolating
the linear portion near the onset of absorption edge to the E=hυ axis. From the Figure
3.5, the optical band gap value is calculated to be 5.5 eV. The wide band gap of the
as grown γ-glycine crystal confirms the 100% transmittance in the UV-vis-NIR
region and less defect concentration of the grown crystal [22]. The observed lower
cutoff wavelength 240 nm of the as grown γ-glycine due to the addition of 2-
aminopyridinium potassium chloride leads to an increase in the band gap of the
compound 5.5 eV.
3.4 Powder XRD studies
The grown γ-glycine crystal crushed to a uniform powder and subjected to
powder x-ray diffractrometer with CuKα (λ=1.540598 Å) radiations for structural
analysis study. The powder form sample was scanned over the range 10-45˚ at the
rate of 2˚/min. The indexed powder XRD pattern of grown crystal is shown in figure
6. Peaks in the XRD without any broadening confirm that the grown sample is higher
order of crystalline nature.
1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
(011
)(0
12)
(001
)(0
02)
(010
)
(101
)
(100
)(0
31)
(110
)
(120
) (200
)(1
11) (2
01)
(002
)
(201
)
(102
)
(112
)
(210
)(0
02)
(112
)
(211
)
(300
)
Inte
nsity
(a.u
)
D i f f r a c t io n a n g le ,2 ( d e g )
2 -A P K C G
Fig 3.6. Powder XRD pattern of as grown crystal γ-glycine
195
3.5 Single crystal XRD analysis
Single crystal X-ray diffraction analysis confirms the hexagonal structure
of the γ-glycine crystal with space group P31. The unit cell parameters of the
grown γ-glycine are a = 7.09Å; b = 7.09Å; c = 5.52Å; α = β = 90˚; γ = 120˚ and
volume of the unit cell was found to be 278 Å3. These values are in-line with the
literature values [23-25]. Further, it is evident that the presence of 2-aminopyridine
potassium chloride in the aqueous solution, without enter into the grown crystal
lattice, yields the polymorph form γ-glycine, as a physical change.
3.6 Thenarmal analysis
Thermo gravimetric (TG) and Differential thermal analysis (DTA) gives
information regarding phase transition, water of crystallization and different stages
of decomposition of the crystal. Samples of γ-glycine crystals were weighed in an
Al2O3 crucible with a microprocessor driven temperature control. TGA and DTA
curves of grown crystals were recorded in nitrogen atmosphere between ambient
temperature to 500˚C shown in Figure 3.7. There is no weight loss up to 216.6˚C
indicating that there is no inclusion of solvent (water) in the crystal lattice. The
thermogram reveals that the major weight loss (42.4%) starts at 216.6˚C and
continues up to 484.4˚C with 1.255mg (57.6%) as residue. The nature of weight loss
indicates the decomposition of the material. Below 484.4˚C no weight loss was
observed.
Temp Cel500.0400.0300.0200.0100.0
DTA
uV
40.00
30.00
20.00
10.00
0.00
-10.00
-20.00
TG m
g
2.800
2.600
2.400
2.200
2.000
1.800
1.600
1.400
1.200
TG %
100.0
95.0
90.0
85.0
80.0
75.0
70.0
65.0
60.0
55.0
50.0
45.0
216.6Cel2.838mg
484.4Cel1.255mg
1.583mg
484.4Cel2.838mg
55.4%
609uV.s/mg
Fig 3.7. TGA& DTA graph of as grown γ-glycine crystal
196
DTA curve shows that the decomposition point of as grown γ-glycine crystal is
270˚C. This decomposition point was compared with the decomposition point of
pure γ-glycine crystal (246˚C) and γ-glycine synthesizes in the presence of different
additives are shown in Table 3.3.
Table 3.3
γ-glycine crystal Decomposition point
In the presence of CoCl 116.86 ˚C [29]
In the presence of CaCl2 265 ˚C [30]
In the presence of AgNO3 208 ˚C [31]
In the presence of Li NO3 195 ˚C [32]
In the presence of LiBr 200 ˚C [33]
In the presence of NH3 145.7 ˚C [34]
In the presence of NaNO3 256 ˚C [35]
In the presence of MgCl2 213 ˚C [36]
In the presence of KCl 170 ˚C [37]
In the presence of KF 259 ˚C [25]
In the presence of HF 240 ˚C [38]
In the presence of H3PO3 &
In the presence of H3PO3 + Urea
51 ˚C [39]
155 ˚C [39]
In the presence of
C5H6N2+KCl**
270 ˚C
** present work
3.7 Dielectric studies
Cut and polished samples of dimensions 11.92 x 8.99 x 3.51mm3 were used
for dielectric measurements. Graphite was applied on opposite sides of the sample
and the dielectric placed between two copper electrodes and thus parallel plate
capacitor was formed. The capacitance of the crystalline sample was measured for
various frequencies in the range 500HZ to 5MHZ at different temperatures. The
dielectric constant was calculated using the formula, Ɛr= Ct/ƐOA Where C, is the
capacitance; t, thickness of the sample; Ɛo, the permittivity of the free sample and A,
197
the area of cross section. Variation of dielectric constant with frequency for the as-
grown crystal of γ-glycine at different temperatures is shown in fig 3.8.The dielectric
constant has higher value at low frequency region and then decreases with the
increase in the frequency. The Ɛr value reached the least value of about 25 at the
applied frequency of 2.5 KHZ and the value remains constant for further frequency.
A similar trend was observed for all the recorded temperatures. Among the all four
polarizations, electronic and space charge polarizations are predominant in the low-
frequency region. The characteristic of low dielectric constant at higher frequency
suggests that the sample possesses an improved optical quality with lesser defects
and this parameter is most important for nonlinear optical materials and their
applications.
2 4 6 8
0
1000
2000
3000
4000
5000
6000
7000
Die
lect
ric C
onst
ant
r
Log f
40o C 45o C 50o C 55o C 60o C
Fig 3.8. Dielectric behavior of γ-glycine crystal
3.8 NLO studies
In order to confirm the NLO property, powdered sample of grown crystal
was subjected to KURTZ and PERRY powder technique, which is a powerful tool
for initial screening of the materials for second harmonic generation (SHG) [26]. The
beam of wave length λ =1064 nm from Q-switched Nd:YAG laser was made to fall
normally on the prepared powdered sample of grown γ-glycine crystal , which was
packed between two transparent glass slides. Suitable solution (CuSO4) was used to
absorb the transmitted beam and the optical second harmonic signal was detected by
a photomultiplier and displayed on CRO. Here powder form of KDP crystal of
identical size to grown γ-glycine crystal powder particles were used as standard in
the SHG measurement.The SHG behavior was confirmed from the emission of
198
bright green radiation (532nm) by the sample. The measured amplitude of second
harmonic green light for as grown γ-glycine crystal was 14.9mJ as against 8.8mJ of
KDP and 8.9mJ of UREA.
Table 3.4 Comparision of SHG efficiency of γ-glycine crystals
γ-glycine crystal # SHG efficiency
In the presence of NaF 1.3[27]
In the presence of NaOH 1.4[27]
In the presence of NaCl/KCl 1.5[28]
In the presence of
NaCH2COOH
1.2[28]
*In the presence of
C5H6N2+KCl
1.65
*Present work, #With reference to KDP
The result shows powder SHG efficiency of as grown γ-glycine crystal is
about 1.65 times that of KDP and 1.63 times of UREA. This value is relatively high
when compared to the SHG values reported for γ-glycine crystals grown with other
additives and comparision is given in Table 3.4. This enhanced lasing performance
of as grown γ-glycine crystal is due to the additive influence of 2-aminopyridinium
potassium chloride. The good second harmonic generation efficiency of as grown γ-
glycine crystal in the presence of 2-aminopyridine potassium chloride attests, that the
grown crystal is a potential candidate for nonlinear optical applications.
5. Conclusion
We have successfully grown polymorph γ-form of glycine single crystals by
slow evaporation solution growth technique at ambient temperature. FTIR & NMR
spectral studies confirm that 2-aminopyridine potassium chloride not entered into the
crystal structure, but they inhibit the growth of polymorph form γ-glycine. UV –
Visible spectral studies show that it has the wide range of transmission from 240nm
to 900nm with cut off wave length 240 nm and the observed high transmittance
percentage (100%) from 240 nm clearly indicates that the grown crystal possessing
good optical transparency for second harmonic generation of Nd:YAG laser. Powder
199
and single crystal XRD studies reveal that the grown γ-glycine crystal is having
higher order of crystallinity. Thermal studies show the sample is thermally stable up
to 270°C and this makes the grown crystal’s suitability for possible application in
laser, where the material is required to with stand high temperatures. Dielectric
studies of grown crystal confirm the improved optical quality. NLO studies of the
grown sample show that the SHG efficiency is greater than KDP (1.65 times) and
Urea (1.63 times) crystals. The grown γ-glycine crystals in the presence of 2-
aminopyridine potassium chloride were possesing various enhanced properties such
as wide transparency range with 100% transmission, low dielectric constant value at
higher frequency and hence improved optical quality with lesser defects and elevated
decomposition temperature (270˚C) with greater SHG efficiency as that of KDP
suggest that the grown γ-glycine crystals in the presence of 2-aminopyridine
potassium chloride is a promising materials for optoelectronic applications.
Acknowledgements
The authors are would like to thank Professor Dr. R. Jayavel, Director,
Academic Research, Anna University, Chennai, for their constant support and
providing facilities to avail various characterization studies for crystals. One of the
author Dr. R. Srineevasan, is grateful to the University Grants Commission, India for
granting Minor project to carry out the research work.
References:
[1].S.Debrus, H.Ratajczak ,J.Venturini, N.Pincon ,J.Baran, J.Barycki,T.Glowiak,
A.pietraszko, Synthetic Metals 127 (2002) 99 – 104.
[2] Ch.Bosshard, K.Sutter, Ph.Pretre, J.Hulliger, M.Florsheimer, P.Kaatz, P.Gunter,
organic Nonlinear optical materials,Gordon and Breach,Basel,1995.
[3] M.C.Etter, J.ChemPhy. 95 (1991) 4601.
[4] C.B.Aakeroy, P.B.Hitchcock, B.D.Moyle, K.R.Seddon, J.Chem.Soc.,
Chem.Commun. (1989)1856.
[5] C.B.Aakeroy, P.B.Hitchcock, B.D.Moyle, K.R.Seddon, J.Chem.Soc.,
Chem.Commun. (1992) 553.
[6] M.Chao, E.Schemp and R.D.Rosenstein, Acta cryst.B31, (1975).2922-2924
[7] D.S.Chemla, J.Zyss(Eds), Nonlinear optical optical properties of organic
molecules and
200
crystals,Academic press,New York,1987.
[8] Yari S. Kivshar, Optics Express, 16, (2008)22126-22128
[9] B. K. Periyasamy, R. S. Jebas, and B. Thailampillai, Materials Letters, 61 (2007)
1489-1491.
[10] K.P.Bhuvana, S.Robinson and T.Balasubramanian,Cryst. Res. Technol,45
(2010) 299-302
[11] Z.kotler, R.Hierle, D.Josse, J.Zyss, R.Masse, J.Opt. Soc. Am. B9(1992) 54
[12] Y.Lefur, M.Bagiue-Beucher, R.Masse, J.F.Nicoud, J.P.Levy, Chem.Mater. 8
(1996) 68.
[13] H.Ratajczak, J.Baran, J.Barycki, S.Debrus, M.May, A.Pietraszko,
H.M.Ratajczak, A.Tramer, J.Mol.Struct. 555 (2000) 149
[14] H.Ratajczak, , S.Debrus, M.May, J.Barycki, J.Baran, Bull. Pol. Acad. Sci.
Chem. 48 (2000) 189.
[15] Katsuyuki Auki, Kozo Pagano, Yoichi Iitaka, Acta Crystallogr. B 27 (1971) 11.
[16] C. Razzetti, M. Ardoino, L. Zanotti, M. Zha, C.
Paorici,Cryst.ResTechnol.37(2002) 456
[17] R.Bairava Ganesh,V.Kannan, R.Sathyalakshmi, P.Ramasami, Mater. Lett. 61,
(2007)706
[18] P. Andreazza, D. Josse, F. Lefaucheux, M. C. Robert, and J. Zyss(1992) Phys.
Rev. B 45, 7640.
[19] M. Narayan Bhat, S.M. Dharmaprakash, J. Crystal Growth. 236 (2002) 376
[20] R.Shanmugavadivu,G.Ravi, A.Nixon Azariah, j. phys. chem.solids 67 (2006)
1858.
[21] N. Ashour, S.A. El-Kadry, Mahmoud, Thin Solid Films 269 (1995) 117–120.
[22] K. Gupta Manoj, Sinha Niahi, Kumar Binay, Phys. B Condens. Matter 406
(2011) 63–67
[23] T.P.Srinivasan,R.Indirajith, R.Gopalakrishnan, J.Cryst.Growth 318 (2011)762-
767.
[24] S.Sankar, M.R.Manikandan, S.D.G.Ram, T.Mahalingam, G.Ravi,
J.Cryst.Growth 312 (2010)2729-2733.
201
[25] G.R. Dillip, P. Raghavaiah, C. Madhukar Reddy, G. Bhagavannaraya, V.
Ramesh Kumar, B. Deva Prasad Raju, Spectrochimica Acta Part A 79 (2011) 1123-
1127.
[26] S.K.Kurtz and T.T.Perry, J.Appl. Phys. 39, (1968). 3798
[27] M.Narayana Bhat, S.M.Dharmaprakash, J.Cryst.Growth 242 (2002) 245.
[28] K.Ambujam, S.Selvakumar, D.Prem Anand, G.Mohamed, P.Sagayaraj,
Cryst.Res. Technol. 401 (2006) 671.
[29]. Jain John, P. Christuraj, K. Anitha, T. Balasubramanian "Materials Chemistry
and Physics” Volume 118, Issues 2–3, 15 (2009) pp. 284–287.
[30]M. Iyanar, J. Thomas Joseph Prakash , C. Muthamizhchelvan, S. Ponnusamy
“Journal of Physical Sciences” Vol. 13 (2009) pp. 235-244.
[31]C. Sekar, R. Parimaladevi “Journal of Optoelectronics and Biomedical
Materials” Vol. 1, Issue 2, (2009), pp. 215–225.
[32]R. Ashok Kumar, R. Ezhil Vizhi, N.Vijayan and D. Rajan Babu., “Physica B”
Volume 406, (2011) Pages 2594-2600.
[33] Balakrishnan, T., Ramesh Babu, R. and Ramamurthi, K.“Spectrochim. Acta
Part A”Vol. 69(2008)pp.1114-1118.
[34] S.A. Martin Britto Dhas, S. Natarajan “ Optics Communications” Vol. 278,
Issue 2, 15 (2007) pp 434–438.
[35] J. Thomas Joseph Prakash, M. Lawrence , J. Felicita Vimala , M. Iyanar
“Journal of Physical Sciences”, Vol. 14, 2010, 219-226.
[36] G.R. Dillip\, G. Bhagavannarayana, P. Raghavaiah, B. Deva Prasad
Raju“Materials Chemistry and Physics” Volume 134 Issue 1 (2012)pp 371–376.
[37] C. Sekar, R. Parimaladevi Spectrochimica Acta Part A, 74 (2009) 1160–1164.
[38] K. Selvaraju, R. Valluvan, S. Kumararaman “Materials Letters” Vol.60, Issue
23 (2006) pp 2848-2850.
[39] S.Kalainathan, M. Beatrice Margaret, “Materials Science and Engineering:B”
Vol.120 (2005) pp.190-193.
202
Structural and optical properties of zinc oxide/magnesium oxide (ZnO/MgO)
nanocomposites synthesized by the facile precipitation process
D. Siva a,, K. Anandan b a, Department of Physics, Shanmuga Industries Arts & Science College,
Thiruvannamailai – 606 601, Tamilnadu, India b Department of Physics, AMET University, Kanathur, Chennai – 603 112,
Tamilnadu, India
Tel.: +91-9597873334 a, +91-9940156552 b
Email id: [email protected] a, [email protected] b
Abstract
Different solvents such as ethanol, ethanol-water and water mediated zinc
oxide/magnesium oxide (ZnO/MgO) nanocomposites have been successfully
synthesized by the facile precipitation process. The structure, purity, crystallite size
and the phase of the synthesized ZnO/MgO nanocomposites are confirmed by the
powder XRD patterns. The functional groups of the samples are confirmed by the
FTIR analysis. The optical properties of the prepared ZnO/MgO samples are
characterized by the UV-visible absorption and the PL emission spectroscopies. The
UV and PL studies are used to determine the band gap, impurity, material quality
and defect levels in the metal oxide nanocomposites.
Keywords: Nanocomposites; ZnO/MgO; Precipitation; Structural; Optical properties
1. Introduction
During*the last few years, synthesis of metal oxide nanocomposite materials
have been attracted considerable attention [1–5]. The metal oxides nanocomposites
are extremely important technological materials for use in optoelectronic and
photonic devices and as catalysts in chemical industries. In recent years, researchers
have focused more on the synthesis of nanocomposite of ZnO/ MgO due to their
application in advanced technologies. Various physicochemical techniques have
been employed to construct nano sized ZnO/MgO nanoparticles [6-17]. Several
techniques have been also developed to prepare nanocomposite of ZnO/MgO. This
nanocomposite has attracted much attention because it has a larger band gap than
ZnO [18-20]. However, most of the techniques need high temperatures and perform
under a costly inert atmosphere. Our goal in this research is to suggest an easy
203
method to synthesize zinc oxide/ magnesium oxide nanocomposite. Considering the
importance of luminescent materials in interdisciplinary materials science and future
optoelectronic applications, the present work is focused on the synthesis of zinc
oxide/magnesium oxide (ZnO/MgO) nanocomposites. They have attracted increasing
interest in fabricating nanostructures with the size and the optical properties could be
achieved by varying the solvents. With this motivation, ZnO/MgO nanocomposites
were prepared by simple precipitation process and their structural, size and optical
properties were studied. The as-synthesized samples are subjected to the different
characterization techniques such as the powder X-Ray Diffraction (XRD), the
Fourier Transform Infrared (FTIR), the Ultraviolet-visible (UV-vis) absorption and
the Photoluminescence (PL) analyzes.
2. Experimental procedure
2.1 Synthesis of ZnO/MgO nanocomposites
The preparation of zinc oxide/magnesium oxide nanocomposites using the
facile precipitation process. All the chemical reagents were commercial with AR
purity, and used directly without further purification. In a typical experiment, 0.1M
of zinc acetate dehydrate (Zn(CH3COO)2∙2H2O) and magnesium acetate tetrahydrate
(Mg(CH3COO)2∙4H2O) were dissolved in 100 ml ethanol. The precipitates were
obtained by the addition of 0.4 M of sodium hydroxide (NaOH) pellets to the above
solution, which was stirred for one hour. The resultant precipitate was filtered,
washed with distilled water and absolute ethanol to remove the impurities, and dried
at 120ºC for 15 hrs. Then, ash colored ZnO/MgO sample was obtained, when dried
sample was calcined at 450ºC for 2h. The same procedure was followed for the
preparation of ZnO/MgO in ethanol-water and water as solvents. The formation of
ZnO/MgO nanocomposites is given in the equation below:
Zn(CH3COO)22H2O
+ + 4NaOH Zn(OH)2/Mg(OH)2 + 4Na(CH3COO) + 6H2O
Mg(CH3COO)24H2O
-------------- (1)
Zn(OH)2/ Mg(OH)2 ZnO/MgO + 2H2O -------------- (2)
204
2.2 Characterization of synthesized nanocomposites
The characterization of metal oxide nanocomposites is essential for
understanding of their structural and optical properties. Due to the inherent
difficulties involved, the scientific experiments for the characterization should have
the ability for rapid collection of data of several parameters with good precision and
accuracy. The development of novel tools and instruments is one of the greater
challenges in nanotechnology. The different solvents mediated samples were
characterized by adopting various physico chemical methods namely XRD, FTIR,
UV-vis and PL. The prepared ZnO/MgO samples were characterized by using the
powder X-ray diffractometer, XPERT PRO with Cuk X-ray radiation (λ=0.15496
nm). The FTIR spectrum of the as-prepared sample was recorded, with a Bruker IFS
66 W Spectrometer using the KBr-pellet technique at a resolution of 4 cm–1 over the
range 4000–400 cm–1. The absorption study of the prepared samples has been carried
out using the Varian Cary 5E UV-vis spectrophotometer. The PL analysis of the
prepared samples was carried out, using the Fluoromax 4 spectrofluorometer, with
an Xe lamp as the excitation light source.
3. Results and discussion
X-ray diffraction (XRD) is a rapid analytical technique primarily used for the
phase identification of a crystalline material, and can provide information on unit
cell dimensions. This method uses a monochromatic source of X-rays and measures
the pattern of diffracted radiation, which is a result of the constructive interference
due to the crystalline structure of the powder. The crystallite size can be obtained
either by direct computer simulation of the X-ray diffraction pattern or from the Full
Width at Half Maximum (FWHM) of the diffraction peaks using the Debye-
Scherrer’s formula [21].
Fig. 1 XRD patterns of ZnO/MgO nanocomposites
prepared in (a) ethanol, (b) water-ethanol and (c)
water D=0.9λ/βcos
205
where,
λ - Wavelength of X-rays,
β - FWHM in radian,
- Peak angle.
Figure 1 (a-c) shows the XRD patterns of ZnO/MgO nanocomposits prepared
in ethanol, ethanol-water and water, respectively. All the peaks in the patterns could
be indexed to the ZnO/MgO nanocomposites. The existence of strong diffraction
peaks at 2 values located at 31.76º, 34.6º, 36.25º, 47.53º and 67.96º corresponding
to (100), (002), (101), (102) and (112) hexagonal wurtzite structure of ZnO crystal
planes (JCPDS Card No.79-205) and peaks at 42.9º, 47.6º , 62.28º and 74.65º,
corresponding to (001), (100), (102) and (110) cubic structure of MgO crystal planes
(JCPDS Card No. 45- 0946), respectively [22]. This fact indicates that the prepared
samples are not a single phase but a composite. Moreover, no impurity such as Zn
(CH3COO)2, Zn(OH)2, Mg(CH3COO)2 and Mg(OH)2 were detected. Peak
broadening indicates that the smaller crystallites size of the prepared ZnO/MgO
nanocomposites.
In any preparation of nanomaterials, the solvent is an important parameter for
determining the crystal size. In the present work, the organic mediated samples (Fig.
1(a-b)) show a slight broadening of peaks compared to the peaks of the aqueous
mediated sample, as shown in Fig.1 (c). This clearly reveals that using organic media
can produce fine particles. Using Scherrer’s formula, the average crystallite sizes of
the ZnO/MgO samples synthesized in ethanol, ethanol-water and water are found to
be 22, 23.91 and 25.82 nm, respectively. From the result it is concluded that the
ethanol mediated ZnO/MgO nanocomposites are most ultra-fine, owing to their best
dispersing and capping ability.
Fourier Transform Infrared (FTIR) spectroscopy is a powerful tool for
identifying the types of chemical bonds (functional groups) in a molecule by
producing an infrared absorption spectrum that is like a molecular "fingerprint". The
wavelength of the light absorbed is characteristic of the chemical bond as can be
seen in this annotated spectrum. Figure 2 shows the FTIR spectra of as-prepared
ZnO/MgO samples dried at 120ºC. The peaks observed in the spectra at 3685-2840,
206
1604 and 1390 cm–1 are the stretching and bending vibrations of –OH groups, which
are associated with the adsorbed water on the surface of the ZnO/MgO particles [23].
Fig. 2 FTIR spectra of (a)
ethanol, (b) water-ethanol
and (c) water mediated
ZnO/MgO samples dried at
120°C
The band appeared at 1096 cm−1 was assigned to the C–N stretching vibration
[24]. Generally, the metal oxides give absorption bands below 1000 cm–1, arising
due to the inter-atomic vibrations. Further, the strong bands located at 746 and 530
cm−1 indicate the stretching vibration mode of Mg–O and Zn–O, respectively, which
confirm the formation of ZnO/MgO nanocomposites [25].
Figure 3 (a-c) shows the UV-vis absorption spectrum of the ZnO/MgO
nanocomposites prepared in ethanol, ethanol-water and water, respectively. It can be
seen in all the spectra that the strong absorption peaks were appeared at around 280
nm, which is attributed to the band gap absorption in ZnO/MgO nanocomposites.
The calculated values of the band gap energies of ethanol, ethanol-water and water
mediated ZnO/MgO nanocomposites are 3.83, 3.75 and 3.66 eV respectively, which
are good agreement with reported band gap values of ZnO/MgO nanocomposites
[28]. Moreover, MgO is more ionic compared to ZnO, because of 3s energy level in
Mg and 4s energy level in Zn. Consequently, the energy difference between these s
levels and O 2p level is smaller in ZnO and larger in MgO. Thus, ionicity is lowest
in ZnO and largest in MgO. This is now consistent with larger band gaps for
ZnO/MgO as compared to ZnO [26].
207
Fig.3 UV-vis absorption
spectra of ZnO/MgO
nanocomposites prepared
in(a) ethanol, (b) water-
ethanol and (c) water
According to the data of the absorption spectra, the optical band gap (Eg) of
the ZnO/MgO nanocomposites can be estimated, by using the following equation:
αh = C (h–Eg)n
Here α is the absorption coefficient, h is the photon energy, C is the
constant, and n=1/2 for a directly allowed transition. For the indirect transitions, the
plots of (αh)2 versus photon energy of the ZnO/MgO nanocomposites are shown in
the inset of Fig. 3. Hence, the optical band gap for the absorption peak can be
obtained by extrapolating the linear portion of the (αh)2–h curve.
Optical investigations can reveal very useful information for understanding
the physical properties of materials. They also demonstrate the possibility of
extending the potential application
of ZnO/MgO nanocomposites in
optoelectronic devices. Therefore,
the photoluminescence emission
measurement was performed with an
excitation wavelength of 300 nm.
Fig. 4 PL emission spectra of
ZnO/MgO nanocomposites
prepared in (a) ethanol, (b) water-ethanol and (c) water
208
Figure 4 (a-c) shows the room-temperature PL emission spectra of ethanol,
ethanol-water and water mediated ZnO/MgO nanocomposites. Generally, ZnO/MgO
nanocomposites grown in the chemical solution has two kinds of defects, i.e.,
intrinsic defect and surface defects. The PL emission spectra of all the samples show
the broad and strong deep level emissions (DLE) in the green emission region
centered at ~ 513–548 and 560 nm, respectively, indicating that the prepared
nanocomposites have a good crystal quality [27]. The DLE is associated with the
intrinsic defects in the ZnO/MgO nanocomposites, and is attributed to the radiative
recombination of photo-generated holes with electrons [28]. Moreover, the DLE
bands are mainly attributed to the intrinsic defects, such as oxygen vacancy, zinc
vacancy, magnesium vacancy, oxygen interstitial, zinc interstitial and magnesium
interstitial or surface-related defects [29, 30]. Since, it was observed from the PL
emission spectra that there was a change in the intensity of the emission peaks by the
alcoholic medium mediated samples (Fig.4.a-b)) than that of aqueous medium,
which lead us to conclude that the alcoholic solvents changed the crystalline size or
increased the intrinsic and surface defect [31].
4. Conclusion
Different solvents such as ethanol, ethanol-water and water mediated
ZnO/MgO nanocomposites have been successfully synthesized by the facile
precipitation process. The hexagonal/cubic structure of ZnO/MgO nanocomposites
was confirmed by the powder XRD patterns and the average particle size of the
samples calculated to be 22, 23.91 and 25.82 nm. It was found that the solvents
played important roles in the preparation of size of nanocomposites. The presence of
functional groups of synthesized ZnO/MgO samples was confirmed by the FTIR
spectrum. The optical properties of the nanocomposites were studied by UV-vis and
PL spectroscopies. The band gap energies of ethanol, ethanol-water and water
mediated ZnO/MgO nanocomposites are 3.83, 3.75 and 3.66 eV respectively, which
are good agreement with reported band gap values of ZnO/MgO nanocomposites.
The PL emission studies showed deep level emissions (DLE) in the green emission
region, indicating that the prepared nanocomposites have a good crystal quality.
Moreover, the DLE bands are mainly attributed to the intrinsic defects, such as
oxygen vacancy, zinc vacancy, magnesium vacancy, oxygen interstitial, zinc
209
interstitial and magnesium interstitial or surface-related defects. Hence, it should be
suitable for optoelectronic devices.
References
[1] F. Nastase, I. Stamatin, C. Nastase, D. Mihaiescu, A. Moldovan, Prog. Solid
State Chem. 34 (2006) 191.
[2] S.H. Yoon, J.S. Kim, Y.S. Kim, Curr. Appl. Phys. 6 (2006) e154.
[3] Y.Q. Huang, L. Meidong, Z. Yike, L. Churong, X. Donglin, L. Shaobo,
Mater. Sci. Eng. B 86 (2001) 232.
[4] Z. Wang, S.K. Saxena, Solid State Commun. 118 (2001) 75.
[5] H. Gong, J.Q. Hu, J.H. Wang, C.H. Ong, F.R. Zhu, Sens. Actuat. B 115
(2006) 247.
[6] Y. Yang, H. Chen, B. Zhao, X. Bao, J. Cryst. Growth 263 (2004) 447.
[7] B.Q. Xu, J.M. Wei, H.Y. Wang, K.Q. Sun, Q.M. Zhu, Catal. Today 68 (2001)
217.
[8] M. Purica, E. Budianu, E. Rusu, M. Danila, R. Gavrila, Thin Solid Films 403–
404 (2002) 485.
[9] Y. Li, Y. Bando, T. Sato, Chem. Phys. Lett. 359 (2002) 141.
[10] J.H. Lee, K.H. Ko, B.O. Park, J. Cryst. Growth 247 (2003) 119.
[11] K.F. Cai, E. Mueller, C. Drasar, A. Mrotzek, Mater. Lett. 57 (2003) 4251.
[12] H.S. Choi, S.T. Hwang , J. Mater. Res. 15 (2000) 842.
[13] T. Lopez, R. Gomez, J. Navarrete, E. Lopez- Salinas, J. Sol-Gel Sci. Technol.
13 (1998) 1043.
[14] R. Ayouchi, D. Leinen, F. Martin, M. Gabas, E. Dalchiele, J.R. Ramos-
Barrado, Thin Solid Films 426 (2003) 68.
[15] Y.Q. Zhu, W.K. Hsu, W.Z. Znou, M. Terrones, H.W. Kroto, D.R.W. Walton,
Chem. Phys. Lett. 347 (2001) 337.
[16] Y.C. Hong, H.S. Uhm, Chem. Phys. Lett. 422 (2006) 174.
[17] Z.M. Dang, L.Z. Fan, S.J. Zhao, C.W. Nan, Mater. Sci. Eng. B 99 (2003) 386.
[18] A. Ohtomo, M. Kawasaki, T. Koida, Appl. Phys. Lett. 72 (1998) 2466.
[19] T. Minemoto, T. Negami, S. Nishiwaki, H. Takakura, Y. Hamakawa, Thin
Solid Films 372 (2000) 173.
210
[20] S. Choopun, R.D. Vispute, W. Yang, R.P. Sharma, T. Venkatesan, Appl.
Phys. Lett. 80 (2002) 1529.
[21] H. R. Wang, K. M. Chen, Colloids and Surfaces A : Physicochem.
Eng.Aspects 281, 190, 2006.
[22] S. Chawla, K. Jayanthi, H. Chander, D. Haranath, S.K. Halder, M. Kar,
Journal of Alloys and Compounds 459, 457–460, 2008.
[23] B.D. Terris, T. Thomson, J. Phys. D: Appl. Phys. 38, 199, 2005.
[24] X. Song, A. Sayari, Catalysis Reviews, Vol. 38, p. 329. 1996.
[25] A. N. Baranov, O. O. Kapitanova, G. N. Panin, T. V. Kang, Russian Journal
of Inorganic Chemistry, 2008, Vol. 53, No. 9, pp. 1366–1370
[26] A.K. Mishra, D. Das, Materials Science and engineering B, 171, 5-10, 2010.
[27] M. Gao, J. H. Yang, L. L. Yang, Y. J. Zhang, H. L. Liu, H. G. Fan, J. H.
Lang, Y. R. Sui, B. Feng, Y. F. Sun, Z. Q. Zhang, H. Song, Appl. Phys. B,
112:539–545, 2013.
[28] X. Liu, X. Wu, H. Cao, RPH. Chang, J. Appl. Phys. Vol. 95, 3141, 2004.
[29] X.H. Wang, D.X. Zhao, Y.C. Liu, J.Y. Zhang, Y.M. Lu, X.W. Fan, J. Cryst.
Growth 263, 316, 2004.
[30] K. Vandheusen, W.L. Warren, C.H. Seager, D.R. Tallant, J.A. Voigt, B.N.
Gnage, J. Appl. Phys. 79, 7983, 1996.
[31] B. Elidrissi, M. Addou, M. Regragui, C. Monty, A. Bougrine, A. Kachouane,
Thin Solid Films Vol. 379, p.23, 2000.
211
ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL ON
THE MICELLATION OF SURFACTANT IN AQUEOUS SOLUTION
AT FIXED FREQUENCY 2 MHZ AND FIXED
TEMPERATURE OF 303.15K.
G. Lakshiminarayanan1 and D. Arun kumar2
1,2Department of Physics, Shanmuga Industries Arts and Science College,Thiruvannamalai.
ABSTRACT
Ultrasonic velocity, density and viscosity studies have been carried out in
aqueous solutions of sodium oleate and in aqueous solutions of sodium oleate
containing 5-20% V/V of ethanol (ET). These studies are carried out in sodium
oleate concentration of 3mM to 12mM at a fixed frequency of 2MHz and at a fixed
temperature of 303.15K. The variation of ultrasonic velocity in aqueous solutions of
sodium oleate containing 5-20% V/V of ET sodium oleate concentration exhibiting a
break at critical micelle concentration (CMC). The ultrasonic velocity, adiabatic
compressibility, free length, free volume and internal pressure also exhibiting a
break at CMC similar to velocity curve. The results are discussed in terms of
formation of sodium oleate micelles through hydrophobic interaction and hydrogen
bonding.
INTRODUCTION
Molecular interaction in liquid mixtures has been the subject of numerous
investigation in recent past years [1-3].The systems shows a wide verity of physical
properties. Resent researchers have studied the interaction of sodium oleate (SO)
with alcohol through ultrasonic techniques. But the effect of ethanol on SO is
scandy. The aim our present investigation is to determine ultrasonic studies on the
effect of ethanol on the micellization of sodium oleate in aqueous solutions at
fixed frequency of 2 MHz and fixed temperature of 303.15 k. The results are
interpreted in terms of formation of SO micelles in the solutions.
MATERIALS AND METHODS
The sodium oleate (SO) used in the present study are of AR/BDH grade
purchased from SD-fine chemicals Ltd., India and they are used as such without
further purification. The solvents used namely ethanol are of spectroscopic grade.
Triply distilled deionised water is used for preparing the solutions of methanol.
212
Ultrasonic velocity studies are carried out at a fixed frequency of 2 MHz in the
sodium oleate concentration range of 3mM to 12mM. Ultrasonic velocity is
measured using a Digital Ultrasonic Velocity meter (Model VCT-70A, Vi-
Microsystems Pvt. Ltd., Chennai, India) at a fixed temperature at 303.15K by
circulating water from a thermostatically controlled water bath and the temperature
being maintained to an accuracy of ±0.1oC. The accuracy in measurement of
velocity and absorption is ±2 parts in 105 and 3% respectively. Shear viscosity and
density of aqueous solutions of SO containing 5-20% V/V of ET are determined
using an Oswald’s viscometer and a graduated dilatometer respectively. The
accuracy in measurement of density and viscosity is ±2 parts in 104 and ± 0.1%
respectively. From the measured values of ultrasonic velocity, density and viscosity,
the various other parameters such as adiabatic compressibility (βs), intermolecular
free length (Lf), free volume (Vf ) and internal pressure (Пi) are calculated using
standard formulae.
COMPUTATIONS OF PARAMETERS
Adiabatic compressibility (βs), intermolecular free length (Lf), free volume
(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),
respectively.
βs = 1/C2ρ (1)
Lf = KT βs 1/2 (2)
Vf = (M C / K η)3/2 (3)
πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)
where, c is ultrasonic velocity, ρ is density, KT is temperature dependant constant, M
is effective molecular weight, K is constant for liquids, b is constant, T is
temperature.
RESULT AND DISCUSSIONS
From the measured values of ultrasonic velocity and viscosity, the other
parameters such as adiabatic compressibility, free length, free volume and internal
pressure were computed and shown in graphically in figures (1-6).The variations of
ultrasonic velocity against concentration of sodium oleate in aqueous solution are
213
given in Fig 1. The measured ultrasonic velocity increases with increasing
concentration of sodium oleate in aqueous solutions and exhibits sharp break at a
particular concentration is known as Critical Micellar Concentration (CMC), which
is confirmed by G.Ravichandran et al [4]. The increase in ultrasonic velocity before
CMC is due to the oleate ions making hydrogen bond with water molecules. The
micelle formation in aqueous solution of sodium oleate and higher aggregation leads
to increase in velocity beyond CMC.
The measured ultrasonic velocity increases with increasing concentration of
sodium oleate in aqueous – alcoholic solvent (5-20%V/V of ethanol) mixtures of
solution and exhibits sharp break at a particular concentration of sodium oleate
(i.e.)., CMC as shown in Fig 1. The increase in ultrasonic velocity is due to the
alcoholic solvents act as a structure breaker in aqueous sodium oleate. Sodium ions
are restricting the mobility of the water molecules. This leads to increase in
ultrasonic velocity before CMC. The micelle formation in aqueous-alcoholic
solution of sodium oleate and higher aggregation leads to increase in velocity after
CMC of solution. In addition to average dipole moment of sodium oleate in the
solution also contributes increase in ultrasonic velocity. The velocity observed in
aqueous-alcoholic solvent at particular compositions (volume by volume) in the
order:
Velocity of 5% ET mixture < Velocity of 10 % ET mixture < Velocity of 15 % ET
mixture < Velocity of 20 % ET mixture
From the figure 1, it is observed that when the 5% V/V of ethanol is added to
the aqueous solution of sodium oleate, the CMC of aqueous solution of sodium
oleate shifted towards the higher concentration side (6.8 mM). This is due to the
lowering of the average dielectric constant of the medium because of the dielectric
constant of water is greater than methanol.
Similarly, when the 10-20% V/V of methanol is added to the aqueous solution
of sodium oleate the CMC of aqueous solution of sodium oleate shifted towards the
higher concentration side in the order of (7.2 mM), (8.4 mM), (8.8 mM),
respectively.
214
0.002 0.004 0.006 0.008 0.010 0.0121560
1565
1570
1575
1580
1585
1590
1595
1600
1605
1610
Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO
Ultr
ason
ic V
eloc
ity (m
s-1)
Molar Concentration of Sodium Oleate
0.002 0.004 0.006 0.008 0.010 0.012
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
Visc
osity
10-4
NSm
-2
Molar Concentration of Sodium Oleate
Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO
0.002 0.004 0.006 0.008 0.010 0.0123.96
3.98
4.00
4.02
4.04
4.06
4.08
4.10
4.12
4.14
4.16
Adi
abat
ic C
ompr
essi
bilit
y( b
s )X1
0-10 N
-1m
2
Molar Concentration of Sodium Oleate
Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO
0.002 0.004 0.006 0.008 0.010 0.0124.13
4.14
4.15
4.16
4.17
4.18
4.19
4.20
4.21
4.22
4.23
Free
Len
gth
L f x 1
0-10 m
Molar Concentration of Sodium Oleate
Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO
Adiabatic compressibility, free length and free volume, internal pressure
studies supports the ultrasonic velocity studies in aqueous and aqueous alcoholic
solvents mixtures.
CONCLUSION
In the present study, the ultrasonic velocity, density, viscosity and internal
pressure increases whereas adiabatic compressibility, free length and free volume
decreases with increasing concentration of sodium oleate in aqueous and aqueous –
alcoholic mixture (Ethanol).
The CMC value obtained in with aqueous with 20 % V/V alcoholic solvent
(Ethanol) mixture is greater than all other compositions of alcohols concentrations of
sodium oleate solutions. This is due to the higher breaking nature of alcohol in
higher compositions.
Figure – 1 Figure - 2
Figure - 3 Figure - 4
215
0.002 0.004 0.006 0.008 0.010 0.0123.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO
Free
Vol
ume
(Vf)
m3
Molar Concentration of Sodium Oleate0.002 0.004 0.006 0.008 0.010 0.012
2.90
2.95
3.00
3.05
3.10
3.15
3.20
3.25
3.30
3.35
3.40
Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO
Inte
rnal
Pre
ssur
e (p
i) pas
cal
Molar Concentration of Sodium Oleate
Figure - 5 Figure – 6
References
1. Bhattarai A, Chatterjee SK, Deo TK, Niraula TP (2011) Effects of
concentration, temperature, and solvent composition on the partial molar
volumes of sodium lauryl sulfate in methanol (1) + water (2) mixed solvent
media. J Chem Eng Data 56:3400–3405
2. Nain AK, et al. Molecular interactions in binary mixtures of formamide with
1 butanol, 2 butanol, 1,3butaneol at different temperatures. Journal of Fluid
Phase Equilibria, 2008; 265(1-2):46-56.
3. Bhoj Bhadur Gurung, Mahendra Nath Roy, Study of densities, viscosities and
ultrasonic speeds of binary mixtures containing 1, 2 diethoxy ethane with
alkane 1-ol at 298.15 K. Journal of Solution Chemistry. 2006; 35:1587-1606.
4. G.Ravichandran, G.rajarajan, T.K. Nambinarayanan, Journal of Molecular
Liquids 267-276, 102 (2003).
216
Synthesis, growth, structure, optical, and photoconducting
properties of an Inorganic new nonlinear optical crystal:
sodium manganese tetra chloride (SMTC)
M. Packiyaraja, D.Sivavishnuc, G.J. Shanmuga Sundarb and
S. M. Ravi Kumarc* aDepartment of Physics, S.K.P. Engineering College, Tiruvannamalai 606 611
3Department of Physics, Arignar Anna Government Arts College, Cheyyar-604 407 cDepartment of Physics, Government Arts College , Tiruvannamalai 606 603
*corresponding author: [email protected]
Abstract
A new inorganic nonlinear optical single crystal of sodium manganese tetra
chloride (SMTC) has been successfully grown form aqueous solution by the slow
evaporation technique at room temperature. The crystals obtained by the above
technique were subjected to different characterization analysis. Single crystal X-ray
diffraction study reveals that the crystal belongs to orthorhombic system with non-
centrosymmetric space group Pbam. Optical transmission study on SMTC crystal
shows high transmittance in the entire UV–Vis region and the lower cutoff
wavelength is found to be 240 nm. The second harmonic generation (SHG)
efficiency of the crystal was measured by Kurtz’s powder technique infers that the
crystal has nonlinear optical (NLO) efficiency 1.32 times that of KDP.
Photoconductivity study confirms that the title compound possesses a negative
photoconducting nature.
1.0 Introduction
The well known properties of laser radiation are important for a wide variety
of applications. Laser radiation could be converted into one form of frequency to
another through the nonlinear optics, hence the application of nonlinear optics is
increased significantly in various fields in science and technology. Generally,
nonlinear optical (NLO) interaction is made by one or two laser beam incident on a
suitable material in which an output beam of the desired frequency is produced [1-2].
Harmonic generation, sum and difference frequency generation and parametric
oscillation are included in the NLO interaction [3]. A Lower frequency pair of
217
tunable output beam can be produced only by suitable material when it is interact
(NLO) with high input laser beam. Mostly, NLO interaction imposes several
demands on potential NLO materials. The field of nonlinear optics is one of the most
attractive fields of current research because of its vital applications in various areas
like optical switching, optical data storage for developing technologies in
telecommunication and signal processing [4-6]. Since, the first demonstration was
done in the year of 1961, which reveals that nonlinear frequency conversion is highly
materials-limited field [7]. So materials should be optically transparent, quadratic
susceptibility of sufficient magnitude, allow for phase matching interaction and
withstand the laser intensity without damaging. To date, the most important class of
materials used in nonlinear optics is inorganic single crystals.
Inorganic materials, exhibiting second order nonlinear optical properties have
attracted in the recent past due to their ability to process into crystals, wide optical
transparency domain, large nonlinear figure of merit for frequency conversion, fast
optical response time and wide phase matchable angle [8]. These ionic bonded
inorganic crystals, easy to synthesis with high melting point and high degree of
chemical inertness[9]. Highly polarisable, inorganic quality crystal and their efficient
active second order harmonic generation (SHG) have been observed by Franken et al
and co-workers in 1961[7].
Inorganic materials have advantages over organic materials, such as
architectural flexibility for molecular design and morphology, high mechanical
strength and good environmental stability with non toxicity andusability in high
power applications. Molecular hyperpolarizability of inorganic nonlinear optical
crystal are used in optical switching (modulation), frequency conversion (SHG, wave
mixing) and electro-optic applications especially in EO modulation. Historically,
inorganic NLO materials have been chronicled more extensively inorganic oxide
crystal, LiNbO3, KNbO3, KDP and KTP, etc., have been studied for device
application like piezoelectric, ferroelectric and Electro-optics [10]. This material has
also been formed successful usage in commercial frequency doublers, mixers and
paramedic generators to provide coherent laser radiation with high frequency
218
conversion efficiency in the new region of the spectrum, inaccessible by other
nonlinear crystal conventional sources.
The aim of this research work is to survey the processing and properties of
inorganic nonlinear optical crystal sodium manganese tetrachloride (SMTC) with
molecular formula Na2MnCl4 used in NLO frequency conversion.The structure of
Na2MnCl4 was determined by Goodyear et al in the year of 1971[11]. The grown
crystals of SMTC, chlorine ions coordinated octahedrally with Mn ions and form an
infinite chain parallel to c axis and are held with sodium ions. Sodium ions are
surrounded by four chloride ions at the corners of a trigonal prism. Binding of Mn-Cl
and Na-Cl suggests that the structure is mainly ionic in character.Hence, an attempt
hasbeen made on growth of sodium manganese tetra chloride (SMTC) single crystals
by slow evaporation solution growth technique and its physical-chemical properties
have been investigated for the first time.
2.0 Experimental Procedure
2.1. Synthesis
SMTC salt was synthesized by taking analytical reagent (AR) grade
manganese chloride and sodium chloride in stoichiometric ratio 1:2 with double
distilled water as a solvent. The synthesized SMTC salt has been obtained by the
following chemical reaction.
MnCl2+2NaCl Na2MnCl4
Manganese chloride + sodium Chloride Sodium manganese tetra chloride.
The scheme of the molecular structure of SMTC is as shown below.
Scheme 1 Molecular arrangement of SMTC crystal
219
2.2 Crystal Growth
The prepared solutions were stirred vigorously at RT for 4 h. Continuous
stirring with slightly rise in temperature ensures homogeneity and avoids co-
precipitation of motives. Purification of synthesized salt was achieved by successive
recrystallization process. The saturated mixture of solution was filtered two times
with micron pore sizeWattmann filter paper. This synthesized clean solution was
poured into a Petri dish and covered by polythene paper with pores, and allowed for
slow evaporation of the water solvent. After a time span of 35 days, the solvent was
evaporated and good quality SMTC crystal of dimensions 22 1 mm3 were
harvested from the Petri dish. The growth rate was found to be 0.12mm per day. The
grown crystal was defect less, optically transparent and with no inclusions. As-
grown crystal of SMTC is shown in the figure 1.
Fig. 1 Photograph of as grown crystals of SMTC
3.0 Characterization of SMTC Single Crystal
The grown crystal of SMTC was subjected to single crystal and powder XRD
analysis using ENRAF NONIOUS CAD4 X-ray diffraction meter and BRUKER,
Germany (model D8 advance) X-ray diffractometer. Transmission behavior of the
grown crystal was studied by using LAMBDA-35 UV-visible spectrophotometer.
The NLO efficiency of the grown crystal was tested by KURTZ powder technique
using ND:YAG laser of wavelength
1064 nm. Mechanical behaviour of the grown sample was investigated by Vicker’s
220
microhardness tester. Dielectric constant and dielectric loss studies were carried out
by using HIOKI3532 HITESTER LCR meter. Keithley 485 PICOAMMETER was
used to study the photoconductivity of the grown SMTC crystal.
3.1 Results and Discussion
3.1.1 Single crystal XRD studies.
The Single crystal XRD study confirms the unit cell parameters of as grown
SMTC crystals a=6.93 Å, b=11. 82 Å, c=3. 86 Å,= β ==90 and volume of the cell
is found to be, 316.182 Å3. Hence the SMTC crystal is Orthorhombic in structure
and in thespace group Pbam. The lattice parameters are well coincide with a reported
value [11].
3.1.2 Linear optical transmission studies
Since NLO crystals can be for practical use only when it has wide
transparency window. The transmission range of SMTC crystal was determined by
recording the optical transmission spectrum in the wavelength region of 200 - 900
nm. The optical transmission spectrum of SMTC crystal is shown in the figure 2.
Optically polished single crystal of thickness 2mm was used to study the
transmission behavior of SMTC. This recorded spectrum, gives information about
the structure of the molecule by absorption of UV and the visible light involves
promotion of electrons in the and orbital from ground state to a higher energy
state [12]. The transmission spectrum shows that the grown crystal has a lower cutoff
wavelength at 240 nm,which attributes the electronic transmission in the SMTC
crystal. Absence of absorbance in the region between 240 nm and 900 nm is an
essential property of the nonlinear optical crystals. Single crystals are mainly used in
optical applications and hence an optical transmittance window and the transparency
lower cutoff wavelength (200-400) is very important for the realization of the SHG
output in the range for using lasers. Optical width of the as grown crystal SMTC
was compared with NaCl and Mncl2 complex inorganic crystals. The grown SMTC
crystal has good transparency in UV-visible and IR region which ensures, that
crystal can be used as sensor materials from UV, visible in the IR ranges and may be
consider as a potential candidate for the photonic and optoelectronic applications
[13]. The graph has been plotted to estimate the direct band gap values using Tauc’s
221
relation. The Tauc’s plot has been drawn between (αhν)2 and hν as shown in the
figure 3. The band gap value is obtained by extrapolating the straight portion of the
graph to hν axis at (αhν)2=0. The estimated band gap value of grown sample SMTC
is 5.4eV.
Fig. 2 UV-Visible spectrum of SMTC crystal
1 2 3 4 5 6 7
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Eg=5.4ev
(alp
ha.h
v)2 .e
v2 .mm
2
hv(ev)
Fig. 3 Tauc’s plot of SMTC crystal
3.1.3 Second harmonic generation efficiency measurement
In order to confirm the nonlinear optical property, powdered sample of
SMTC was subjected to Kurtz and Perry techniques, which remains a powerful tool
for initial screening of materials for SHG [14]. The fundamental beam of wavelength
1064 nm from Q switched mode locked Nd:YAG laser was made to fall normally on
the powder from of grind sample which was made available between two transparent
222
glass slides. Pulse energy 2.9 mJ/pulse and pulse width 8 ns with a repetition rate of
10 Hz were used. The photo multiplier tube (Hamamatsu R2059) was used as a
detector and 90 degree geometry was employed. The SHG signal generated in the
sample was confirmed from emission of bright green (532 nm) radiation from the
sample. The measured amplitude of second harmonic generation for SMTC crystal is
11.32 mJ and 8.8 mJ for KDP (KDP crystal was powdered to the identical size of
SMTC and used as reference materials). It shows a powder SHG efficiency of SMTC
crystal is about 1.3 times of KDP. The SHG efficiency of SMTC crystal is compared
to few popular inorganic NLO crystals which are given in the table 1.
3.1.4 Photoconductivity studies.
The photoconductivity study of SMTC crystal was carried out by connecting
the sample in series with DC power supply and a picoammeter (Keithley 480) at
room temperature. The details of the experimental setup are reported elsewhere [15].
By increasing the applied field from 10 to 150 V/cm and corresponding dark current
without exposure of radiation was recorded. Photo current was recorded by exposing
the crystal with halogen lamp of power 100 W containing iodine vapour for the same
applied field. Dark current and Photo current against an applied field of same range
were recorded in the same graph [Figure 4]. From the graph, it is observed that dark
and photo current of the grown crystal increase linearly with applied field but
photocurrent less than the dark current. This phenomenon is termed as negative
photoconductivity.
Negative photo conductivity of being as grown crystal SMTC, may be due to
decrease in either no number of free change carriers or their lifetime when subjected
to radiation. Negative Photoconductivity of the grown crystal explained, according to
Stockman model, the forbidden gap in the material contains two energy levels in
which one is situated between the Fermi level and the conduction band while another
is located close to the valence band. The second state has a high capture cross section
for electrons and holes. As it captures electrons from the valence band the number of
charge carriers in the conduction band gets reduced and the currentdecreases in the
presence of radiation [16-18].
223
Fig. 4 Field dependent conductivity of SMTC crystal
4.0 Conclusion
A potential inorganic nonlinear optical single crystal of sodium manganese tetra
chloride was prepared at room temperature by slow evaporation of aqueous
solutions. The well defined external appearance with bright, transparent and
colourless crystals is obtained. The unit cell parameters and the space group were
found using single crystal data. The FT-IR spectrum reveals the functional groups of
the grown crystals. The grown crystal shows 99 % transmission with UV cut-off at
240 nm hence suitable for frequency conversion applications. The SHG efficiency of
the SMTC was measured to be higher than that of KDP. The above experimental
results, viz., bulk size, extremely good crystalline perfection, optical transparency,
SHG efficiency and photoconducting nature of the grown crystal may have possible
NLO applications.
Reference
[1] A. H. Reshak, H. Kamarudin, and S. Auluck, Acentric Nonlinear Optical 2,4-
Dihydroxyl Hydrazone Isomorphic Crystals with Large Linear, Nonlinear
Optical Susceptibilities and Hyperpolarizability, J. Phys. Chem. B 2012, 116,
4677−4683.
[2] Ali Hussain Reshak , I. V. Kityk , and S. Auluck, Investigation of the Linear and Nonlinear Optical Susceptibilities of KTiOPO4 Single Crystals: Theory and Experiment, J. Phys. Chem. B 2010, 114, 16705-16712
0 20 40 60 80 100 120 140 1600.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Curr
ent (
nA)
Electric Field (V/cm)
Id(dark current)
Iph(photocurrent)
224
F. Peter, M.Bordui and Martin,Fejer.Annu. Rev. Mater. Sci. 23 (1993) 321-379.
[3] P.N. Prasad, D.J. Williams. Introduction to nonlinear optical effects in organic molecules and polymers, John Wiley & Sons, Inc., New York, USA (1991).
[4] H.O. Marcy, L.F. Warren, M.S. Webb, C.A. Ebbers, S.P. Velsko, G.C. Kennedy, G.C. Catella, Second harmonic generation in zinc tris(thiourea) sulfate, Appl. Opt. 31 (1992) 5051-5060.
[5] X.Q. Wang, D. Xu, D.R. Yuan, Y.P. Tian, W.T. Yu, S.Y. Sun, Z.H. Yang, Q. Fang, M.K. Lu, Y.X. Yan, F.Q. Meng, S.Y. Guo, G.H. Zhang, M.G. Jiang, Synthesis, structure and properties of a new nonlinear optical material: Zinc cadmium tetrathiocyanate, Mater. Res. Bull. 34 (1999) 2003-2011.
[6] P.A. Franken, A.E. Hill, C.W. Peters, G.Weinreich, Generation of optical harmonics, Phys. Rev. Lett. 7 (1961) 118-119.
[7] H. Nalwa, Seizo Miyata.Nonlinear optics of organic molecules and polymers, CRC press, New York (1996).
[8] C.F. Dewey Jr, W.R. Cook Jr, R.T. Hodgson, J.J. Wynne,Frequency doubling in KB5O84H2O and NH4B5O84H2O to 217.3 nm, Appl. Phys. Lett. 26 (1975) 714–716.
[9] D.S. Chemla, J. Zyss, Nonlinear optical properties of organic molecules and crystals. 01-02, Academic Press, Orlando, New York (1987).
[10] J. Goodyear, S.D.A. Ali, G.A. Steigmann, The crystal structure of Na2MnCl4,
ActaCryst. B27 (1971) 1672-1674. [11] R. Sankar, C.M. Raghavan, M. Balaji, R. Mohan Kumar, R. Jayavel,
Synthesis and Growth of Triaquaglycinesulfatozinc(II), [Zn(SO4)(C2H5NO2)(H2O)3], a New Semiorganic Nonlinear Optical Crystal, Cryst. Growth Des. 7 (2007) 348-353.
[12] Y. Le Fur, R. Masse, M.Z. Cherkaoui, J.F. Nicoud, Z. Kristallogr. 856 (1993). [13] S.K. Kurtz, New nonlinear optical materials, IEEE, J. Quantum Electron. 4
(1968) 578–584. [14] F.P. Xavier, A. Regis Indigo, G.J. Goldsmith, Role of metal phthalocyanine in
redox complex conductivity of polyaniline and aniline black, J. PorphyrinsPhthaloeyanines 3 (1999) 679-686.
[15] V.N. Joshi, Photoconductivity, Marcel Dekker, NewYork, (1990). [16] S. Abraham Rajasekar, K. Thamizhrasan, J.G.M. Jesudurai, D. Premanand, P.
Sagayaraj, The role of metallic dopants on the optical and photoconductivity properties of pure and doped potassium pentaborate (KB5)single crystal. Materials Chemistry and Physics. 84(1) (2004)157-161.
[17] Owczarek,K. Sangwal,Effect of impurities on the growth of KDP crystals: On the mechanism of adsorption on 100 faces from tapering data, J. Cryst. Growth. 99 (1990) 827-831.
225
SYNTHESIS, STRUCTURAL, OPTICAL AND MORPHOLOGICAL
PROPERTIES OF (Co, Ag) doped ZINC OXIDE NANOPARTICLES
J.Balavijayalakshmi a*, K.Meenab
aAssistant Professor, Department of Physics, PSGR Krishnammal College for
Women, Coimbatore, Tamilnadu, INDIA. bPG Student, Department of Physics, PSGR Krishnammal College for Women,
Coimbatore, Tamilnadu, INDIA
Abstract
Co-Ag co-doped Zinc oxide nanoparticles are synthesized by chemical co-
precipitation method. Zinc Chloride, Cobaltous chloride, Silver nitrate and sodium
hydroxide is used as raw materials. The synthesized nanoparticles are subjected to
X-ray diffraction technique to calculate the average nano-crystalline size using
Debye – Scherrer formula and are found to be around 25 nm. The optical properties
are characterized by UV-Vis spectral analysis. The FT-IR spectrum of the sample is
recorded and the characteristic absorption bands are observed. The morphological
analysis of the sample is studied using Scanning Electron Microscope (SEM). These
co-doped (Co, Ag) ZnO nanoparticles may be used as antibacterial reagents to treat
diseases caused by bacteria and fungi.
Keywords: Co-precipitation method, nanoparticles, Debye – Scherrer, FT-IR,
SEM.
1. INTRODUCTION
Zinc oxide nanoparticles have attracted great attention in recent years because
of its unique properties and versatile applications in transparent electronics,
ultraviolet (UV) light emitters, piezoelectric devices, chemical sensors and
spintronics [1-4]. ZnO has high chemical stability and low toxicity, which is widely
used as an active ingredient for dermatological applications in creams, lotions and
ointments on an account of its antibacterial properties [5-7]. Doped ZnO shows
maximum effect against pathogenic organisms as compared to ZnO, there by using
nanoparticles as an antimicrobial agent. Many Literatures have reported the
structural, optical and morphological properties of pure ZnO, Co doped ZnO and Ag
doped ZnO by various methods such as hydrothermal, thermal hydrolysis, sol-gel
and chemical precipitation methods [ 8-12]. Among these methods, co-precipitation
226
method is cost-effective with high yield. Hence in the present investigation, an
attempt is made to synthesize Co-Ag co-doped Zinc oxide nanoparticles by chemical
co-precipitation method.
2. MATERIALS AND METHODS
The chemicals Zinc chloride, Silver nitrate, Cobalt chloride, Sodium
hydroxide used in this study is of analytical grade. Cobalt doped silver nanoparticles
are synthesized by taking stoichiometric amounts of 0.05 aqueous solution of silver
nitrate, 0.85M aqueous solution of zinc chloride and 0.10 M aqueous solution of
cobaltous chloride. The solutions are mixed together. The neutralization is carried
out with sodium hydroxide and the pH of the solution is maintained at 9. Then the
solution is washed with de-ionised water until all the impurities are removed and the
sample is annealed at 500C.
The crystal structure of the synthesized samples is analyzed using XRD
Shimadzu 6000. The FT-IR spectra are recorded using Shimadzu IR affinity-1 to
ensure the presence of the metallic compounds. UV-Visible absorption spectra are
recorded using the SHIMADZU UV-Visible absorption Spectrometer. The
morphology and the microstructure of the samples are tested by scanning electron
microscopy (SEM) using a Hitachi S-3000H microscope.
3. RESULTS AND DISCUSSION
3.1 XRD Structural Analysis
Figure 1. XRD spectrum of Zn0.85Co0.10 Ag0.05O annealed at 500 C
227
X-ray diffraction pattern of (Co,Ag) doped ZnO nanoparticles annealed at
500 C is shown in Figure 1. The diffractograms showed the characteristic
reflections planes corresponding to (100), (002), (101), (102), (110), (103), (112) and
(201) crystal planes. The peaks are well matched with reference to the JCPDS card
no 36-1451, corresponding to hexagonal wurtzite structure of ZnO [13-14]. It is
observed that the inclusion of cobalt and silver with ZnO have not modified its
wurtzite structure. But the characteristic peak of Ag corresponding to (200) plane is
observed. The peaks are sharper and narrower as the samples are annealed at 500C,
indicating the crystalline nature of the sample. The average particle size (D) is
calculated using the Scherrer formula [15]
D = 0.9λ/(β cosθ)
Where D is the crystalline size, λ is the wavelength of the X-ray radiation, θ is the
diffraction angle, β is the full width at half maximum of the diffraction peak at 2θ.
The average crystallite size from X-ray technique is found to be 22-25 nm.
3.2 FT-IR Spectral Analysis
4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0 5 0 0
7 5
8 0
8 5
9 0
9 5
1 0 0
1 0 5
Tran
smitt
ance
(%)
W a v e n u m b e r ( c m - 1 )
Figure 2. FT-IR spectrum of Zn0.85Co0.10Ag0.05O annealed at 500 C
The FT-IR spectrum of Zn0.85Co0.10 Ag0.05O annealed at 500 C in the wave
number range 4000-400 cm-1 is shown in Figure 2. The absorption bands observed
around 3452cm-1 is attributed to O-H stretching vibrations and the band around
2969cm-1 is due to C-H vibrations. The absorption band around 1720 cm-1 are due to
CO vibrations. The absorption band around 1368 cm-1 is due to ZnO [16-17] and the
band around 720cm-1 corresponds due to the presence of silver ions [18-19].
228
3.3 UV Spectral Analysis
200 300 400 500 600 700 8000.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
Abs
orba
nce
Wavelength(nm)
Figure 3. UV-Vis spectrum of Zn0.85Co0.10 Ag0.05O annealed at 500 C
UV Visible spectroscopy is used to study the optical properties of Zn0.85Co0.10
Ag0.05O nanoparticles measured at room temperature in the wavelength range of 200
– 800 nm as shown in Figure 3. The absorption band is observed at 380 nm due to
ZnO nanoparticles. Three additional absorption bands are observed at 565nm, 655nm
and 676nm in the spectra of (Co,Ag) doped ZnO nanoparticles. These additional
absorption bands are due to the co-doping of cobalt and silver ions in ZnO. This may
be attributed due to the sp-d exchange interaction between the band electrons and the
localized d electrons of the dopants [20-21].
3.4 SEM Analysis
Figure 4. SEM micrograph of Zn0.85Co0.10 Ag0.05O annealed at 500 C
Figure 4 shows the scanning electron micrograph of Zn0.85Co0.10 Ag0.05O
nanoparticles annealed at 500C. The micrograph shows sphere like bubbles
distributed uniformly and agglomerated together.
229
4. CONCLUSION
(Co,Ag) doped ZnO nanoparticles (Zn0.85Co0.10 Ag0.05O) nanoparticles are
synthesized by chemical co-precipitation method. The synthesized nanoparticles are
subjected to X-ray diffraction technique to calculate the average nano-crystalline size
using Debye – Scherrer formula and are found to be around 22-25 nm. The optical
properties are characterized by UV-Vis spectral analysis and three additional peaks
are observed. The FT-IR spectrum of the sample is recorded and the characteristic
absorption bands are observed. SEM analysis show regular sphere like bubbles.
These co-doped (Co, Ag) ZnO nanoparticles may be used as antibacterial reagents to
treat diseases caused by bacteria and fungi.
5. REFERENCES
1. Ezenwa I.A., Synthesis and optical characterization of zinc oxide thin film,
Research Journal of Chemical Sciences,2(3), 26-30 (2012).
2. Yang H.M., Nie S., Preparation and characterization of Co-doped ZnO
nonmaterial’s, Mater. Chem. Phys., 114, 279-282 (2009).
3. Yang M., Guo Z.X., Qiu K.H., Long J.P., Yin G.F., Guan D.G., Liu S.T.,
Zhou S.J., Synthesis and characterization of Mn-doped ZnO column arrays,
Appl. Surf. Sci., 256, 4201- 4205. (2010).
4. Irimpan L., Nampoori V.P.N., Radhakrishnan., Spectral and nonlinear optical
characteristics of nanocomposites of ZnO- Ag, Chemical Physics Letters.,
455, 265-269 (2008).
5. Jones, N., Ray, B., Ranjit, K.T., Manna, A.C., Antibacterial activity of ZnO
nanoparticle suspensions on a broad spectrum of microorganisms, Fem.
Microbial. Lett.279, 71-76 (2008).
6. Tam, K.H., Djurisic, A.B., C.M.N. Chan, C.M.N., Xi,Y.Y., Tse, C.W., Leung,
Y.H., Chan, W.K., Leung, F.C.C.,Au, D.W.T., Antibacterial activity of ZnO
nanorods prepared by a Hydrothermal method, Thin Solid Films., 516, 6167 -
6174 (2008).
7. Zhang, L., Ding, Y., Povey, M., York, D., ZnO nanofluids a potential
Antibacterial agent, Prog. Nat. Sci., 18, 939-944 (2008).
230
8. Georgekutty, R., Seery, M.K., Pillai, S.C., A Highly Efficient Ag-ZnO
Photocatalyst: Synthesis, Properties, and Mechanism, J. Phys. Chem. C., 112,
13563-13570 (2008).
9. Zheng, Y., Chen, C., Zhan, Y., Lin, X., Zheng, Q., Wei,K., Zhu, J., Photocatalytic Activity of Ag/ZnO Heterostructure Nanocatalyst: Correlation between Structure and Property, J. Phys. Chem.C.112, 10773 -10777 (2008).
10. Ye X-Y., Zhou Y-M., Sun Y-Q., Chen J., Wang Z-Q., Preparation and characterization of Ag/ZnO composites via a simple hydrothermal route, J. Nanopart. Res. 11, 1159-1166 (2009)
11. Nirmala, M., Anukaliani, A., Characterization of undoped and Co doped ZnO nanoparticles synthesized by DC thermal plasma method, Physica B, 406, 911- 915 (2011).
12. Zhang, Y., Shi, E.W., Chen, Z.Z., Magnetic properties of different temperature treated Co- and Ni-doped ZnO hollow nanospheres, Mater. Sci. Semicond. Process, 13, 132-136 (2010).
13. Pal, B., and Giri, P.K., High temperature ferromagnetism and optical properties of Co doped ZnO nanoparticles, J.Appl. Phys. 108, 084322-1 - 084322- 8 (2010)
14. Zeferino, R.S., Flores, M.B. and Pal, U., Photoluminescence and Raman scattering in Ag-doped Research Journal of Material Sciences ZnO nanoparticles, J. Appl. Phys. 109, 014308-1 - 014308-6 (2011).
15. Cullity B.D., Elements of X-ray diffraction, Addison-Wesely., 1959. 16. Ahmed F., Kumar S., Arshi N., Anwar M.S., Koo B.H.,Lee C.G., Doping
effects of Co2+ ions on structural and magnetic properties of ZnO nanoparticles, Microelectronic Engineering 89, 129-132 (2012).
17. Ullah R., Dutta J., Photocatalytic degradation of organic dyes with manganese-doped ZnO nanoparticles, Journal of Hazardous Materials, 156, 194-200 (2008).
18. S. Suwanboon. Structural and optical properties of nanocrystalline ZnO powder from sol-gel method, Sci. Asia 34(1), pp. 31-34, (2008).
19. A. H. Shah, E. Manikandan, M. Basheer Ahmed and V. Ganesan. Enhanced Bioactivity of Ag/ZnO Nanorods-A Comparative Antibacterial Study. J. Nanomed Nanotechol 4(3), pp.2-6, (2013).
20. Ruby Chauhan, Ashavani Kumar and Ram Pal Chaudhary, Synthesis and characterization of silver doped ZnO nanoparticles, Archives of Applied Science Research, 2 (5):378-385 (2010).
21. Xiao Q., Zhang J., Xiao C., Tan X., Photocatalytic decolorization of methylene blue over Zn1-xCoxO under visible irradiation, Materials Science and Engineering: B, 142, 121-125 (2007).
231
Assessment of Heavy metal Pollution in Coastal Sediments of East Coast of
Tamilnadu using Energy dispersive X-ray Fluorescence Spectroscopy (EDXRF)
N. Harikrishnan1, M. Suresh Gandhi2, Durai Ganesh1, A. Chandrasekaran3,
R. Ravisankar1*
1Post Graduate and Research Department of Physics, Government Arts College,
Thiruvannamalai - 606603, Tamilnadu, India 2Department of Geology University of Madras Guindy Campus, Chennai -600025,
Tamilnadu,India 3Department of Physics, SSN college of Engineering, Kalavakkam, Chennai -
603110, Tamilnadu, India
Email: [email protected]; +91-9840807356
Abstract
The heavy metals concentration and its pollution status of sediments from
Periyakalapattu to Parangipettai of East Coast of Tamilnadu, India were investigated
using EDXRF technique. The concentration of heavy metals Mg, Al, Si, K, Ca, Ti,
Fe, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Ba, La and Pb were determined using energy
dispersive X-ray fluorescence (EDXRF) technique. The mean concentration of heavy
metal found in the order of Mn > Ba > V > Cr > Zn > La > Ni > Si > Pb > Co > As >
Cd > Cu > Al > Fe > Ca > Ti > K > Mg. The pollution indices like contamination
factor (CF), contamination degree (Cd) and modified degree of contamination (mCd)
were calculated to assess the contamination status of metals in sediments. The results
of pollution indices shows that Al, Mg, Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu, As, Ba,
La and Pb are low degree of contamination whereas high degree of contamination
for Cd. This work may be serves as baseline work for future.
Key Words: Sediment, EDXRF, Contamination Degree (Cd), Modified Degree of
Contamination (mCd).
232
1.Introduction
Pollution of the natural environment by metals is becoming a potential global
problem. Coastal and estuarine regions are the important sinks for many persistent
pollutants and they accumulate in organisms and bottom sediments (Szefer et al.,
1995). Sediment pollution by heavy metals has been regarded as a critical problem in
marine environment because of their toxicity and bioaccumulation (Chapman et al.,
1998; Islam and Tanaka, 2004; Singh et al., 2005; Todd et al., 2010). Sediment
analysis is vital to assessing qualities of total ecosystem of a water body in addition
to water sample analysis practiced for many years.
Sediment quality has been recognized as an important indicator of water
pollution (Larsen and Jensen 1989) since sediments are the main sink for various
pollutants, including metals discharged into the environment (Williams et al., 1996;
Balls et al., 1997; Dassenakis et al., 1997; Tam and Wong 2000). Multi-elemental
analysis of sediment may reveal the presence of heavy metals and may have toxic
influence on ground water and surface water and also on plants, animals and humans
(Suciu et al., 2008).
In this work, sediments are addressed for monitoring and assessment of metal
pollution from Periyakalapattu to Parangipettai of East Coast of Tamilnadu, India.
The study area chosen for the heavy metals analysis due to variety of industrial
activities (such as metal smelting, pharmaceuticals etc) and agriculture activities
(which include maize, cassava, sugarcane and vegetables farming) takes place and
may enhance the pollution level. These activities may release toxic and potentially
hazards to the environment of the study area. So this research is geared up to assess
the metal pollution and influence of sources from the toxic metals on the sediments
from East Coast of Tamilnadu. The main objective of this work is (1) to determine
concentrations of metals present in sediments from Periyakalapattu to Parangipettai
of East Coast of Tamilnadu using EDXRF technique (2) to identify the level of
heavy metal contamination status using pollution indices (3) to find out the sources
of heavy metals influenced by of natural and/or anthropogenic (4) to report the
findings.
233
2. Materials and Methods
2.1. Sampling and sample preparation
Sediment samples were collected along the Bay of Bengal coastline, from
Periyakalapattu to Parangipettai coast of Tamilnadu. These samples were collected
in pre-monsoon season, where sediment texture and ecological conditions can be
clearly observed, when erosional activities are predominant, and sediments were not
transported from the river and estuary towards the beach and marine. In order to
ensure minimum disturbance of the upper layer, samples were collected by a
Peterson grab sampler from seabed. The grab sampler collects sediment from the
seabed along the 15 stations (Fig.1).
Table 1. Geographical latitude and longitude for the sampling locations
S.
No
Name of the
Location
Location
ID Latitude Longitude
1 Periyakalapet PKP 12° 1' 46.6320'' N 79° 51' 49.0032'' E
2 Ellaipillaichavady EPC 11° 55' 54.0228'' N 79° 48' 19.1268'' E
3 Auroville ARV 11°59'2.8422"N 79°50'55.5334"E
4 Nadukuppam NDK 11°58'1.7401"N 79°38'35.5103"E
5 Muthialpet MTP 11° 57' 18.2556'' N 79° 50' 4.1712'' E
6 Veerampattinam VMP 11° 54' 5.6160'' N 79° 49' 36.7428'' E
7 Nallavadu NVD 11° 51' 27.6014'' N 79°34'27.46"E
8 Narambai NRB 11° 49' 3.2520'' N 79° 48' 0.9216'' E
9 Thazhankuda TZK 11°46'14.2020"N 79°47'40.5605"E
10 Cuddalore OT COT 11° 45' 0.0000'' N 79° 45' 0.0000'' E
11 Raasapettai RSP 11° 40' 56.2692'' N 79° 46' 17.5008'' E
12 Sitheripettai STP 10° 30' 31.6944'' N 77° 13' 17.7600'' E
13 Betlodai BLD 11° 21' 45.2300'' N 79° 32' 21.8544'' E
14 Samiyarpettai SYP 11° 32' 57.2100'' N 79° 45' 31.8744'' E
15 Parangaipettai PGP 11° 30' 0.0000'' N 79° 46' 0.0012'' E
234
Table 1 represents the geographical latitude and longitude for the sampling
locations at the study area. The sampling locations were selected based on the
prevailing stresses and included areas near the urban and domestic effluent discharge
point. Uniform quantity of sediment samples were collected from all the sampling
stations located between an average interval of 3NM (Nautical mile) and the sample
was kept in a thick plastic bag. Care was taken to ensure that the collected sediments
were not in contact with the metallic dredge of the sampler, and the top sediment
layer was scooped with an acid washed plastic spatula. Sediment samples were
stored in plastic bags and kept in refrigeration at -4ºC until analysis. Then pebbles,
leaves and other foreign particles were removed. The samples were sub sampled
using the coning and quartering method. The sub samples were air dried and larger
stone fragments (>20mm largest diameter) or shells were removed. The samples
were air dried at 105ºC for 24 h to a constant weight and were not separated <63 µm
in order to identify the geochemical concentrations in the whole bulk fraction as the
study area is dominated by sandy layers in many places. Then samples were ground
into a fine powder for 10-15 min, using an agate mortar. All powder samples were
stored in desiccators until they were analyzed.
2.2. EDXRF technique
The prepared pellets were analyzed using the EDXRF available at
Environmental and Safety Division, Indira Gandhi Centre for Atomic Research
(IGCAR), Kalpakkam, Tamilnadu. The instrument used for this study consists of an
EDXRF spectrometer of model EX-6600SDD supplied by Xenemetrix, Israel. The
spectrometer is fitted with a side window X-ray tube (370W) that has Rhodium as
anode. The power specifications of the tube are 3-60kV; 10-5833µA.
Selection of filters, tube voltage, sample position and current are fully
customizable. The detector SDD 25mm2 has an energy resolution of 136eV ± 5eV at
5.9keV Mn X-ray and 10-sample turret enables keeping and analyzing 10 samples at
a time. The quantitative analysis is carried out by the In-built software nEXT. A
standard soil (NIST SRM 2709a) was used as reference material for standardizing
the instrument. This soil standard obtained from a follow field in the central
235
California San Joaquin valley. The soil standard (reference material) (NIST SRM
2709a) analysis value are given in Table 2.
Table-2 Analysis of soil standard-NIST SRM 2709a by EDXRF (mg kg-1)
Element Certified Values EDXRF values
Mg 14600 14900 ± 1000
Al 72100 68400 ± 2300
K 20500 19100 ± 700
Ca 19100 16500 ± 500
Ti 3400 3100 ± 100
Fe 33600 33900 ±1200
V 110 98.8 ± 6.59
Cr 130 112.1 ± 4.01
Mn 529 568.2 ± 19.85
Co 12.8 12.8 ± 0.55
Ni 83 69.3 ± 2.98
Zn 107 127.9 ± 4.88
3.0. Results and discussion
3.1. Metal contents in surface sediments
The concentration of elements in sediments from Periyakalapattu to
Parangipettai along the East Coast of Tamilnadu, southeastern, India is presented in
Table 3. The concentration varies from 25 to 6007 mg kg-1 for Mg; from 13532-
37425 mg kg-1 for Al; from 129139-226500 mg kg-1; from 4468-9350 mg kg-1 for K;
from 4592-21679 mg kg-1 for Ca; from 530-51434 mg kg-1 for Ti; from 3647-57902
mg kg-1 for Fe; from 23.4-711 mg kg-1 for V; from 12.5-207.3 mg kg-1 for Cr; from
68.1-1387.6 mg kg-1 for Mn; from 1.1-19 mg kg-1 for Co; from 15.2-33.63 mg kg-1
for Ni; from BDL-3.60 mg kg-1 for Cu; from 14-89 mg kg-1 for Zn; from 4-7.4 mg
kg-1 for As; from BDL-10.2 mg kg-1 for Cd; from 152.3-416.8 mg kg-1 for Ba; from
BDL-216.7 mg kg-1 for La and from BDL-35.7 mg kg-1 for Pb. The enhancement of
heavy metal (Cr, Mn, Co, Ni, Cu, Zn, As and Cd) concentration in the study area
may be due to many fisher man and tourist activities along the east coast of
236
Tamilnadu in the sediment. Among the heavy metals determined, Aluminum (Al) is
the most abundant metal in the sediments. The mean of metal concentration
decreased in the following order, Si > Al > Fe > Ca > Ti > K > Mg > Mn > Ba > V >
Cr > Zn > La > Ni > Pb > Co > As > Cd > Cu in the study area (Chandrasekaran et
al., 2015).
The locations of Auroville (ARV), Nadukuppam (NDK), Veerampattinam
(VMP), Nallavadu (NVD), Narambai (NRB) is characterized by higher
concentrations of Al, Ti, Fe, V, Cr, Mn, Co & Zn when compared with other
locations. This may be due to the high tourists’ boat activities and other
anthropogenic activities like shipping and harbor activities, industrial and urban
wastage discharges, dredging, etc., (Ravisankar et al., 2015).
From the analysis, the elevated heavy metal levels in the sediments resulted
partially from the anthropogenic activities such as wastewaters, aquaculture activities
and shipping. Table 4 shows the comparison of heavy metal (mg kg-1) concentration
of present work with other countries.
3.2. Contaminant factor (Cf)
Contaminant factor (Cf) is the ratio obtained by dividing the concentration of
each metal in the sediment by the background value (Håkanson, 1980). Cf is
considered to be an effective tool in monitoring the pollution over a period of time
and is given by the formula,
‘‘Cbackground’’ refers to the concentration of metal indicates the concentration
of metal (of interest) in the sediments when there was no anthropogenic input.
According to Håkanson (1980): Cf<1 indicates low contamination; 1<Cf<3 is
moderate contamination; 3<Cf<6 is considerable contamination; and Cf > 6 is very
high contamination.
237
Fig 1. Location map of the study area
238
Table 3. Heavy metal concentration (mg kg-1) of sediment samples of east coast of Tamilnadu, India
S.
No Element Mg Al Si K Ca Ti Fe V Cr Mn Co Ni Cu Zn As Cd Ba La Pb
1 PKP 2223 20696 223285 6615 8943 2039 9534 50.11 42.38 192.26 3.38 20.86 BDL 30.54 4.7 5.5 312.4 12.9 4.4
2 EPC 25 20255 216248 6202 7239 2340 8458 50.9 30.3 180.1 2.8 19.8 BDL 23.0 4.7 2.1 306.1 29.1 1.5
3 ARV 1800 37425 226500 5484 8070 51434 57902 711.0 207.3 1387.6 19.0 24.4 BDL 89.0 6.9 BDL 180.2 216.7 35.7
4 NDK 300 13532 210618 6800 4592 530 3647 23.4 12.5 68.1 1.1 15.2 BDL 14.0 4.0 BDL 411.9 BDL BDL
5 MTP 1028 19066 189935 7869 7406 1216 5520 26.37 21.21 110.05 1.88 16.48 BDL 20.16 4.8 10.2 385.4 BDL 1.4
6 VMP 6007 30893 161332 5044 20809 15464 35269 234.71 127.00 750.16 12.51 33.63 BDL 62.31 6.5 3.4 209.0 47.0 17.0
7 NVD 3022 26895 133697 4468 21176 11689 33771 204.56 123.33 748.38 11.95 33.30 BDL 65.67 5.8 BDL 152.3 31.0 19.8
8 NRB 5051 31132 150205 4850 21679 19539 40489 310.87 155.77 869.09 14.35 30.23 3.60 65.94 7.4 BDL 176.0 51.2 25.5
9 TZK 816 21212 147446 6085 12057 3357 13407 64.94 54.52 243.11 5.01 23.21 BDL 30.78 5.2 1.4 256.7 19.1 9.1
10 COT 1608 19866 129139 5392 11628 3776 13137 71.38 55.33 263.74 4.61 24.59 BDL 29.00 4.7 3.6 236.1 6.4 6.1
11 RSP 795 23554 178547 7286 11363 931 8308 31.85 43.85 157.81 3.10 22.84 BDL 22.47 4.8 2.3 308.2 0.0 6.8
12 STP 1773 22928 202630 9350 11586 724 6693 28.12 30.32 128.35 2.40 21.67 BDL 36.02 5.6 1.8 416.8 1.0 7.6
13 BLD 2072 20975 179547 7147 9403 1583 9530 40.01 66.16 185.61 3.42 23.16 BDL 25.08 4.9 3.8 302.5 3.1 5.5
14 SYP 3440 21775 136994 4859 13169 3469 19281 86.6 112.3 112.3 6.5 32.1 BDL 37.8 4.4 5.1 250.4 18.0 5.0
15 PGP 4612 25167 134370 5232 12027 8814 24594 151.9 118.1 118.1 8.3 30.4 BDL 45.0 5.0 2.8 224.0 6.0 9.4
Average 2305 23691 174699 6179 12076 8460 19302 139.11 80.03 367.65 6.68 24.80 3.60 39.79 5.3 3.8 275.2 36.8 11.1
239
Table 4. Comparison of heavy metal (mgkg-1) concentration of present work
with other countries
S
No
.
Location Cr Mn Co Ni Zn References
1 Tinto River,
Spain 11-151 -
6.8-
42 1.6-36
68-
5280
Morillo et al.,
(2002)
2 Bremen Bay,
Germany 131 - - 60 790
Hamer and
Karius, (2002)
3 Danube River,
Europa
26.5-
556.5
442-
1655 -
17.5-
173.3
78-
2010
Woitke et al.,
(2003)
4 Pearl River
estuary 89 - - 41.7 150 Zhou et al., (2004)
5 Masan Bay,
Korea 67.1 - - 28.8 206.3
Hyun et al.,
(2007)
6 Kafrain Dam,
Jordan 160 730 60 100 120
Ghrefat et al.,
(2011)
7
East Coast of
Tamilnadu,
India
115.18 427.5 6.96 32.48 43.63 Ravisankar et al
(2015)
8
Periyakalapat
tu to
Parangipettai
coast,
Tamilnadu,
India
80.03 367.65 6.68 24.80 39.79 Present Study
240
The Contaminant Factor in sediments from Periyakalapattu to Parangipettai,
along the East Coast of Tamilnadu, southeastern India is presented in Table 5. The
results of Cf'’s are 0.002 to 0.400 (average 0.154) for Mg, 0.15 to 0.43 (average
0.27) for Al, 0.17 to 0.35 (average 0.23) for K, 0.29 to 1.35 (average 0.75) for Ca,
0.12 to 11.18 (average 1.84) for Ti, 0.08 to 1.23 (average 0.41) for Fe, 0.18 to 5.47
(average 1.07) for V, 0.14 to 2.30 (average 0.89) for Cr, 0.08 to 1.63 (average 0.43)
for Mn, 0.06 to 1.00 (average 0.35) for Co, 0.31 to 0.67 (average 0.50) for Ni, 0.15
to 0.94 (average 0.42) for Zn, 0.00 to 0.08 (average 0.01) for Cu, 0.31 to 0.57
(average 0.41) for As, 0.00 to 34.07 (average 9.35) for Cd, 0.26 to 0.71 (average
0.47) for Ba, 0.00 to 2.36 (average 0.32) for La and 0.00 to 1.78 (average 0.52)
respectively with the order of Cd > Ti > V > Cr > Ca > Si > Pb > Ni > Ba > Mn > Zn
> Fe > As > Co > La > Al > K > Mg > Cu.
The Cf values of the elements Co, Ni, Cu, & As indicates low contamination
where as moderate contamination noticed for the elements Cr & Cd. The high
contamination was observed in most of the locations (Muthialpet (MTP – 34.07);
Periyakalapet (PKP – 18.19); Samiyarpettai (SYP – 16.91); Betlodai (BLD – 12.77);
Cuddalore OT (COT – 12.14); Veerampattinam (VMP – 11.26); Parangaipettai (PGP
– 9.41); Raasapettai (RSP – 7.80) and Ellaipillaichavady (EPC – 7.00) for Cd. The
location Auroville (ARV) registered high values for the elements Cr, Co & Zn in Cf .
The Cf value of the elements Ni & As noticed high value in the locations of
Veerampattinam (VMP – 0.67) and Narambai (NRB – 0.57) respectively. The
enrichment of heavy metals may originate from non-point sources such as
agricultural pollution (e.g, fertilizers and livestock manure), atmospheric transport
and other industrial activities). The heavy metals accumulation can be attributed to
other sources such as municipal waste waters, mine discharge, irrigation discharge,
and local rivers and creeks, along with erosion of rocks and parent soil materials
(Dai et al., 2007; Cheng and Hu, 2010; Hosono et al., 2011). Fig 4 shows the
variation in CF values of heavy metals with locations.
241
Fig 4. Variation of CF values of heavy metals in locations
3.3. Contamination degree (Cd)
To facilitate pollution control, Hakanson (1980) proposed a sediment logical
approach using a diagnostic tool named the ‘degree of contamination’. Cd was
determined as the sum of the Cf for each sample:
----------------- (2)
For contamination degree, Hakanson (1980) proposed this classification: Cd<6
indicates a low degree of contamination; 6<Cd<12 is a moderate degree of
contamination; 12<Cd<24 is a considerable degree of contamination; and Cd > 24 is
a high degree of contamination, indicating serious anthropogenic pollution. The
calculated Contamination degree value of 0.47 for Al; 0.40 for Mg; 0.35 for K; 1.35
for Ca; 11.18 for Ti; 1.23 for Fe; 5.47 for V; 2.30 for Cr; 1.63 for Mn; 1.00 for Co;
0.67 for Ni; 0.94 for Zn; 0.08 for Cu; 0.07 for As; 34.07 for Cd; 0.72 for Ba; 2.36 for
La and 1.78 for Pb .The obtained Contamination degree value for the elements Al,
Mg,Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu, As, Ba, La & pb shows the low degree of
contamination. Ti shows the moderate degree of contamination whereas Cd
exhibited high degree of contamination from its value of 34.07. This may be due to
recent increase in major industrial (in the coastal areas) and a minor harbor activity
that involves movement of naval vessels throughout the year may increase the
contamination levels in coastal areas. Table 5 shows the contamination degree (Cd)
of sediment samples of east coast of Tamilnadu, India. Fig 5 shows the variation of
Cd values of heavy metals in locations.
242
Table 5. Contamination factor (Cf), Contamination Degree (Cd) and Modified Degree of Contamination (mCd) of sediment
samples of east coast of Tamilnadu, India
Element S.
No Location
ID
Si Al Mg K Ca Ti Fe V Cr Mn Co Ni Zn Cu As Cd Ba La Pb
1 PKP 0.81 0.24 0.148 0.25 0.56 0.44 0.20 0.39 0.47 0.23 0.18 0.42 0.32 - 0.36 18.19 0.54 0.14 0.22
2 EPC 0.79 0.23 0.002 0.23 0.45 0.51 0.18 0.39 0.34 0.21 0.15 0.40 0.24 - 0.36 7.00 0.53 0.32 0.08
3 ARV 0.82 0.43 0.120 0.21 0.50 11.18 1.23 5.47 2.30 1.63 1.00 0.49 0.94 - 0.53 - 0.31 2.36 1.78
4 NDK 0.77 0.15 0.020 0.26 0.29 0.12 0.08 0.18 0.14 0.08 0.06 0.31 0.15 - 0.31 0.00 0.71 - -
5 MTP 0.69 0.22 0.069 0.30 0.46 0.26 0.12 0.20 0.24 0.13 0.10 0.33 0.21 - 0.37 34.07 0.66 - 0.07
6 VMP 0.59 0.35 0.400 0.19 1.30 3.36 0.75 1.81 1.41 0.88 0.66 0.67 0.66 - 0.50 11.26 0.36 0.51 0.85
7 NVD 0.49 0.31 0.201 0.17 1.32 2.54 0.72 1.57 1.37 0.88 0.63 0.67 0.69 - 0.44 - 0.26 0.34 0.99
8 NRB 0.55 0.35 0.337 0.18 1.35 4.25 0.86 2.39 1.73 1.02 0.76 0.61 0.69 0.08 0.57 - 0.30 0.56 1.27
9 TZK 0.54 0.24 0.054 0.23 0.75 0.73 0.28 0.50 0.61 0.29 0.26 0.46 0.32 - 0.40 4.78 0.44 0.21 0.45
10 COT 0.47 0.23 0.107 0.20 0.73 0.82 0.28 0.55 0.61 0.31 0.24 0.49 0.31 - 0.36 12.14 0.41 0.07 0.30
11 RSP 0.65 0.27 0.053 0.27 0.71 0.20 0.18 0.24 0.49 0.19 0.16 0.46 0.24 - 0.37 7.80 0.53 - 0.34
12 STP 0.74 0.26 0.118 0.35 0.72 0.16 0.14 0.22 0.34 0.15 0.13 0.43 0.38 - 0.43 5.94 0.72 0.01 0.38
13 BLD 0.65 0.24 0.138 0.27 0.59 0.34 0.20 0.31 0.74 0.22 0.18 0.46 0.26 - 0.37 12.77 0.52 0.03 0.28
14 SYP 0.50 0.25 0.229 0.18 0.82 0.75 0.41 0.67 1.25 0.13 0.34 0.64 0.40 - 0.34 16.91 0.43 0.20 0.25
243
15 PGP 0.49 0.29 0.307 0.20 0.75 1.92 0.52 1.17 1.31 0.14 0.44 0.61 0.47 - 0.38 9.41 0.39 0.07 0.47
Average 0.64 0.27 0.15 0.23 0.75 1.84 0.41 1.07 0.89 0.43 0.35 0.50 0.42 0.01 0.41 9.35 0.47 0.32 0.52
Contamination
Degree (Cd) 0.47 0.40 0.35 1.35 11.18 1.23 5.47 2.30 1.63 1.00 0.67 0.94 0.08 0.07 34.07 0.72 2.36 1.78
Modified Degree of
Contamination
(mCd)
0.22 0.13 0.19 0.63 1.53 0.34 0.89 0.74 0.366 0.29 0.41 0.35 0.004 0.34 7.79 0.40 0.27 0.43
- N.D – Not determined
Fig 5. Shows the variation in Cd and mCd values of heavy metals in locations
244
3.4. Modified degree of contamination (mCd)
The modified degree of contamination was introduced to estimate the overall
degree of contamination at a given site according to the formula (Abrahim and
Parker, 2008):
----------- (3)
For the classification and description of the modified degree of contamination
(mCd) in sediments, the following gradations are proposed: mCd<1.5 is nil to a very
low degree of contamination; 1.5 < mCd<2 is a low degree of contamination; 2<
mCd <4 is a moderate degree of contamination; 4< mCd<8 is a high degree of
contamination; 8< mCd <16 is a very high degree of contamination; 16< mCd <32 is
an extremely high degree of contamination; mCd >32 is an ultra-high degree of
contamination.
The calculated modified degree of contamination value 0.22 for Al; 0.13 for
Mg; 0.19 for K; 0.63for Ca; 1.53 for Ti; 0.34 for Fe; 0.89 for V; 0.74 for Cr; 0.36 for
Mn; 0.29 for Co; 0.41 for Ni; 0.35 for Zn; 0.004 for Cu; 0.34 for As; 7.79 for Cd;
0.40 for Ba; 0.27 for La and 0.43 for Pb. From obtained values of modified degree of
contamination of Al, Mg, K, Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu, As, Ba, La & Pb
registered very low degree of contamination. Ti noticed low degree of contamination
from its value of 1.53 whereas Cd showed high degree of contamination of its value
7.79. Table 5 shows the modified degree of contamination (mCd) of sediment
samples of east coast of Tamilnadu, India. Fig 5 shows the variation of mCd values
of heavy metals in locations.
4.0. Conclusion
Distribution of Mg, Al, Si, K, Ca, Ti, Fe, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd,
Ba, La, and Pb in sediment samples were determined along the east coast of
Tamilnadu using EDXRF technique.
The mean concentration of studied elements followed as Al > Fe > Ca > Ti >
K > Mg > Mn > Ba > V > Cr > Zn > La > Ni > Pb > Co > As > Cd > Cu.
245
The obtained mean concentration values are compared with different
countries.
The results of pollution indices Al, Mg ,Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu,
As, Ba, La Pb shows low degree of contamination from contamination degree
(Cd) and modified degree of contamination (mCd).
The heavy metals Cd noticed high contamination from the contamination
degree (Cd) and modified degree of contamination (mCd) values. This may be
due to anthropogenic activities in the study area.
This work may be more extensive studies in this filed for future plans.
Acknowledgement
We are sincerely thanks and gratitude to Dr. K. K. Satpathy, Head,
Environment and Safety Division, RSEG, EIRSG, Indira Gandhi Centre for Atomic
Research (IGCAR), Kalpakkam- 603 102 for giving permission to make use of
EDXRF facility in RSEG and also our deep gratitude and thanks to Dr. M. V. R.
Prasad, Head, EnSD, RSEG, IGCAR, Kalpakkam- 603102, India for his keen help
and constant encouragements in EDXRF measurements. Our sincere thanks to Mr.
K. V. Kanagasabapathy, Scientific Officer, RSEG, IGCAR for his technical help in
EDXRF analysis.
Reference
Abrahim, G.M.S., Parker, R.J., 2008. Assessment of heavy metal enrichment factors
and the degree of contamination in marine sediments from Tamaki Estuary
Auckland, New Zealand. Environ. Monit. Assess. 136, 227–238.
Balls, P. W., Hull, S., Miller, B. S., Pirie, J. M., & Proctor, W. (1997). Trace metal in
Scottish estuarine and coastal sediments. Marine Pollution Bulletin, 34, 42–
50.
Chandrasekaran A, Ravisankar R, Harikrishnan N, Satapathy KK, Prasad MVR,
Kanagasabapathy KV. Multivariate statistical analysis of heavy metal
concentration in soils of Yelagiri Hills, Tamilnadu, India – Spectroscopical
approach. Spectrochim Acta Part A 2015; 137: 589–600.
Chapman, P.M., Wang, F., Janssen, C., Persoone, G., Allen, H.E., 1998.
Ecotoxicology of metals in aquatic sediments binding and release,
246
bioavailability, risk assessment, and remediation. Can. J. Fish. Aquat. Sci. 55,
2221–2243.
Dassenakis, M., Scoullos, M., & Gaitis, A. (1997). Trace metals transport and
behaviour in the Mediterranean estuary of Acheloos river. Marine Pollution
Bulletin,34, 103–111.
Ghrefat HA, Abu-Rukah Y, Rosen MA.Application of geoaccumulation index and
enrichment factor for assessing metal contamination in the sediments of
Kafrain Dam, Jordan Environ Monit Assess 2011; 178:95-109.
Håkanson, L., 1980. Ecological risk index for aquatic pollution control: a sediment
logical approach. Water Res. 14, 975–1001.
Hamer K, Karius V. Brick production with dredged harbour sediments.An industrial-
scale experiment. Waste Management 2002; 22:521–30.
Hyun S, Lee CH, Lee T, Choi JW. Anthropogenic contributions to heavy metal
distributions in the surface sediments of Masan Bay, Korea.Mar Pollut Bull
2007; 54:1059-68.
Islam, M.S., Tanaka, M., 2004. Impacts of pollution on coastal and marine
ecosystems including coastal and marine fisheries and approach for
management: a review and synthesis. Mar. Pollut. Bull. 48, 624–649.
Larsen, B., & Jensen, A. (1989). Evaluation of the sensitivity of sediment monitoring
stationary in pollution monitoring. Marine Pollution Bulletin, 20,556–560.
Morillo J, Usero J, Gracia I. Heavy metal fractionation in sediments from the Tinto
River (Spain), Int J Environ Anal Chem 2002; 82:245–57.
Ravisankar, R., Sivakumar, S., Chandrasekaran, A., Kanagasabapathy, K.V.,
Prasad, M.V.R., Satapathy, K.K., 2015. Statistical assessment of heavy metal
pollution in sediments of East Coast of Tamilnadu using Energy dispersive X-
247
ray fluorescence spectroscopy (EDXRF). Applied Radiation and Isotopes.
102, 42-47.
Singh, K., Mohan, D., Singh, V., Malik, A., 2005. Studies on distribution
andfractionation of heavy metals in Gomti river sediments – a tributary of the
Ganges, India. J. Hydrol. 312, 14–27.
Suciu, I., Cosma, C., Todica, M., Bolboaca, S. D. and Jantschi, L. (2008): Analysis
of soil heavy metal pollution and patern in central Transylvanian. Int. J. Mol.
Sci. 9: 434 – 453.
Szefer P, Glassby GP, Pempkowiak J, Kaliszan R. Extraction studies of heavy metal
pollutants in surficial sediments from the southern Baltic Sea off Poland.
Chem Geol 1995;120:111–26.
Tam, N. F. Y., & Wong, W. S. (2000). Spatial variation of metals in surface
sediments of Hong Kong mangrove swamps. Environmental Pollution, 110,
195–205.
Todd, P.A., Ong, X., Chou, L.M., 2010. Impacts of pollution on marine life in
Southeast Asia. Biodivers. Conserv. 19, 1063–1082.
Williams, T. M., Rees, J. G., Kairu, K. K., & Yobe, A. C.(1996). Assessment of
contamination by metals and selected organic compounds in coastal
sediments and waters of Mombasa, Kenya. Technical Report W C-96-37, 85.
Woitke P, Wellmitz J, Helm D, Kube P, Lepom P, Litheraty P. Analysis and
assessment of heavy metal pollution in suspended solids and sediments of the
river Danube, Chemosphere 2003; 51:633–42.
Zhou HY, Peng XT, Pan JM. Distribution, source and enrichment of some chemical
elements in sediments of the Pearl River Estuary, China. Continental Shelf
Research 2004; 24:1857–75.
248
SYNTHESIS, GROWTH AND PHYSICOCHEMIC AL PROPERITIES OF
DIAMMONIUM TETRACHLORO ZINCATE NLO CRYSTALS (DTCZ)
*S.M.Ravikumar and 1G.Nathiya
*Asst. professor, PG& Research Department of physics, Govt. Arts college
Tiruvannamalai-606 603
1Asst. professor, PG& Research Department of physics, Shanmuga Industries Arts and
ScienceCollege, Tiruvannamalai-606 601
ABSTRACT
Diammonium tetrachlro zincate was synthesized by taking diammonium chloride
and zinc chloride in 2:1. New crystals of ATCZ were grown by slow evaporation of an
aqueous solution at room temperature. The grown crystals were characterized by
powder X-ray diffraction (PXRD) analysis, FTIR studies, UV-visible studies. Dielectric
studies and photoconductivity studies and NLO activity of the grown crystal have been
checked by second harmonic generation (SHG) test. The grown crystals have been
subjected to powder X-ray diffraction to identify the crystalline nature. FTIR analyses
was done to confirm the present of various functional group in (DTCZ) crystalline using
Nd-YAG laser the NLO property of the crystal is studied. The transmittance and
absorption of the crystal was studied by UV-Visible spectrometer. Dielectric constant
and dielectric loss were identified by using HIOKI model 3532-50 LCR HITESTER.
The photo conducting nature of the grown crystal was studied by pico ammeter (
Keithly 485 ).
KEY WORDS: Solution growth, FTIR, XRD, SHD, Optical material.
INTRODUCTION:
Non-linear optics is a very useful technology because it extends the usefulness of
lasers by increasing the number of wavelength available both longer and
Shorter than the original can be produced by non-linear optics.
A versatile and highly efficient non-linear optical frequency conversion material
is of vital importance for many applications in the field of photonics and
249
optoelectronics. The interest of the researchers on NLO crystal is not confined just to
their NLO properties. Among these materials show large non-linear linearity, low
angular sensitivity and good mechanical hardness.
NLO crystals has emerged as one of the most attractive field of current research
in view of its vital applications in areas like optical modulation, optical switching,
optical logic frequency shifting and optical data storage for the developing technologies
in telecommunication and inefficient signal processing[1-5].
The search for new, very efficient non-linear materials, for fast and optimum
processing of optical signals has become very important, because of development of
optical fiber communication, laser based imaging and remote sensing etc. In many of
the organic NLO materials there is a solid framework of conjugated electronics along
with weak Vander Waals and hydrogen bonds which are responsible for their NLO
properties.
4 techniques at room temperature. The grown crystals were subjected to various
characterization studies like structure analyze by single and powder diffraction and the
presence of functional groups in the sample was investigated by Fourier transform
infrared spectrometer. The linear and non-linear optical property were carried by UV-
VIS absorption spectrometer and Kurtz and Perry Powder technique. The dielectric
behavior was analyzed. The photo conducting nature of the crystal has been carried out.
EXPERIMENTAL PROCEDURE:
SYNTHSIS OF ATCZ:
Required amount of the commercially available ammonium chloride and Zinc
chloride taken in the molar ratio (2:1) were dissolved in double distilled water to
synthesis diammonium tetra chlro salt. All the starting materials were of analytical
reagent (AR) grade. The synthesis salt was obtained by the following chemical reaction.
2(NH4Cl) + Zncl2 – (NH4)2 cl4Zn
2( Ammonium chloride ) + Zinc chloride –Diammonium tetra chloride Zincate
250
The solution was stirred for about 3 hours using a magnetic stirrer to yield a
homogenous mixture.
Growth of ATCZ crystal
The saturated of diammonium tetra chloro zincates was prepared double distilled
water. The solution was filtered and poured into the Petri was covered by transparent
sheet with few holes were made on it. The solution was kept in undisturbed condition.
The solution was allowed to evaporate slowly. After 10 to 15 days, good transparent
seed crystals were harvested. In the period 30 -35 days, the crystal with dimension
25x8x4 mm3 was obtained. The growth crystal has no inclusion, free from impurities,
defect free with good transparent nature. As grown crystal of ATCZ is shown in the
figure 1.0
Fig: 1.0 photograph of as grown crystal of ATCZ
CHARACTERISATION METHODS:
Single crystal XRD is rescored using Enraf CAD-4 diffractometer with MOKα
(λ=0.1770Ao) radiation. Powdered XRD spectrum of the crystal is recorded using
Rigaku X-ray diffractometer with CuKα radiation. FTIR spectra of Diammonium
tetrachlro zincate was record using a beuker IFS66 FTIR spectrophotometer at room
temperature in the range 400-4000cm-1 by KBr pellet method. The optical absorption
spectrum of ATCZ was studied in the wavelength range 190-900nm by a Varian carry
5E model spectrophotometer. To confirm the non-linear optical property Kurtz and
Perry powder SHg test was carried out for the grown crystal using Nd:YAG Q-
251
switched laser emitting the first harmonic output of 1064nm. The temperature
dependent dielectric constant and dielectric loss was carried out by using a HIOKI
3532-LCR Hit ester. The photo conducting nature of the grown sample was investigated
by PICO Ammeter ( keithley 485 ).
Single crystal X-ray diffraction:
Single crystal X-ray diffraction analysis was carried out using an Enraf CAD-4
diffractometer with MOKα (λ=0.1770Ao) radiatuion. From this analysis it was
observed that the grown crystal of ATCZ belongs to orthorhombic crystal system
having non- centrosymmetry space group with Pmc21.Lattice parameters have been
determined as:a =12.6197,b=7.2107 and c=9.2746 Ao;α=β=ϒ=90 which are in good
agreement with the reported values[6].
Powder X-ray diffraction:
Powder X-ray diffraction data were collected for the grown single crystals. The
pattern was recorded using a Raiku X-ray diffractometer with MOKα (λ=0.1770Ao)
radiation. The powdered sample was scanned in the range 10-90oc at a scan rate of
2/min. In the powder XRD pattern well
defined peaks are observed which reveals
that the grown crystal ATCZ has highly
crystalline nature. The various planes of
ATCZ crystal has been indexed in the
powder XRD pattern. The observed
PXRD pattern of ATCZ is shown in the
fig 1.1
Fig 1.1: powder x-ray diffraction spectrum
252
Fourier Transform Infrared (FTIR) spectroscopy studies:
The infrared spectral analysis is effectively used to understand the chemical
bonding and it provides information about molecular structure of the synthesized
compound. Crushed powder of diammonium tetra chloro zincate crystal was pelletized
using KBr. The spectrum was recorded using a thermo Nicollet v-200 FTIR
spectrometer in the range 400-4000 cm-1 wave number region. The FTIR spectrum of
ATCZ is shown in fig.1.2
The peak around 3196, 2378 cm-1 is due to N-H stretching vibration. The peak at
2988.2795 cm-1 is O-H stretching. The peak of IR spectrum at 2378, 2203 cm-1 is due to
stretching of C≡C. The peak around 1887, 1844 cm-1 is due to C=O stretching vibration.
A peak at 1651 cm-1 has been assigned to C=C stretching vibration. The peak obtained
at 1553 cm-1 for N=O stretching vibration. A
peak 1381 cm-1 is due to C-H deformation. C-C
stretching curve obtained at 997 cm-1. Stretching
of C-Cl are assigned at 676,603 cm-1 stretching
vibration of C-Br are assigned at 577 cm-1. The
band assignment of FTIR spectrum of
Diammonium tetra chloro zincate (ATCZ).
Crystal details shown in table 1.0
Fig 1.3: FTIR spectrum of ATCZ crystal
Table 1.0: Bands assignments of FTIR spectra of ATCZ
Wave number(cm-1) Assignments
3196,2378 N-H Stretching
2988,2795 O-H Stretching
2378,2203 N-H Stretching
1887,1884 N=O Stretching
253
1651 N-H deformation
1553 N=O Stretching
1381 N=O asymmertric
577 NH3+ Torsional oscillation
Optical absorption study:
The grown crystals of pure ATCZ were cut and polished into plates of suitable
dimension to carry out the optical transmission studies. A spectrum was recorded in the
region 190-900 nm using VARIAN CARY 5E model spectrophotometer. The UV-VIS
NIR transmission spectrum of ATCZ crystal is shown in the Fig 1.2.In the UV visible
and IR region, the material found to be transparent. This transparent nature extends the
application of ATCZ in photonics. It is well known that an efficient NLO crystal has an
optical transparency loe cut-off wavelength between 200 and 400nm. The crystal shows
good transmittance in the visible region and the lower cut-off wavelength is 22onm.
Fig 1.2 UV-VIS-NIR spectra of ATCZ single crystal
NLO test:
The SHG property of the grown crystal was tested by the Kurtz and Perry
powder method [7].The powdered sample of ATCZ crystal was illuminated using the
fundamental beam of 1064nm from Q-Switched ND:YAG laser. A photomultiplier tube
(Hamamatsu R2059) was used as the detector and the 90 degree geometry was
employed. The light emitted from the sample was detected by a detector and measured
254
using an oscilloscope. Second harmonic radiation generated by the randomly oriented
micro crystals was focused by a lens and detected by a detector. The optical signal
generated from the sample was converted into an electrical signal and was measured an
oscilloscope. The output of ATCZ is 8.6mJ and it is compared to standard value of
potassium dihydrogen phosphate (KDP) is 8.8mJ. Hence it was found that SHG
efficiency of growth crystal is almost equivalent to KDP.
Dielectric study:
Figure 1.3 and 1.4 show the variations of dielectric constant and dielectric loss
with log frequency for as grown crystal of ATCZ. The dielectric constant of the sample
was measured for different frequencies under various temperature slots from 308 K and
368 K. It is observed from the plot (fig 1.3) that the dielectric constant constant
exponentionally with increasing frequency and then attains almost a constant value in
the high frequency region starting from 3KHz to 6MHz. The similar trend is also
observed form figure 5.6 that the dielectric loss is decreases with increasing frequency
and attains constant after the frequency of 2.5MHz. It is observed that at all
temperatures, both the dielectric constant and dielectric loss decrease with increasing
frequency.
At lower frequency, the dielectric constant is high due to blocking of charge
carrier at electrodes. With increasing temperature, a high degree of dispersion in the
permittivity occur at lower frequency due to space charge effect.
The characteristics of low dielectric
constant and dielectric loss with high frequency
for a given sample suggests that the sample
possesses enhanced optical quality with lesser
defects and this parameter is of vital importance
for various nonlinear optical materials and their
applications[8].
Fig.1.3 Variation of dielectric constant with log frequency for ATCZ
255
Fig1.4 Variation of dielectric loss with log frequency for ATCZ
Photoconductivity study:
Photoconductivity study of the ATCZ single crystal was carried out by using
keithly 485 picoammeter. By not allowing any radiation to fall on the sample and by
varying applied field from 100 to 3000 V/cm, the corresponding dark current values
shown by the picoammeter were recorded. To measure the photo current, the sample
was illuminated with a halogen lamp (100W) containing iodine vapor by focusing a spot
of light on the sample with help of a convex lens. The applied field was increased from
100 to 3000 V/cm and the corresponding photo current was record. The photo current
and dark current are plotted as a function of the applied field (Fig 1.5). It is observed
from the plot that the dark current is always higher than the photo current, hence it is
concluded that ATCZ exhibits negative photoconductivity. The stockman model also
explains the phenomenon of negative photo conductivity successfully.
Fig 1.5 Field dependent photoconductivity of ATCZ single crystal
256
CONCLUSION:
Single crystal of ATCZ was grown by slow evaporation technique. The single
crystal XRD reveals that crystal belongs to orthorhombic crystal system with non
centrosymmetry space group pmc21. The crystalline nature and various planes are
identified by powder XRD. The various functional groups presented in ATCZ was
conferred by FTIR studies. The UV cut-off wavelength was determined in 210nm,
which is main property for NLO application.SHG studies reveals that ATCZ equals to
known NLO material KDP. The variation of dielectric constant at dielectric loss was
analyzed. The grown crystal exhibited negative photo conductivity nature.
REFERENCES:
1. Nalwa H S & Miyata S,Non-linear optics of organic Molecules and polymers
(CRC press,Newyork)1997.
2. Prasad P N & Willams DJ, Introduction to Non-linear optical effects in Organic
molecules and polymersb(Wiley, Newyork),1991.
3. Hann R A & Bloor D (Eds), Organic materials for Non-linear optics, (The Royal
society of chemistry),1989.
4. Badan J,Hiere R,Perigand A, et al (Ed), Non-linear optical properities of organic
molecules and polymeric materials, American chemicals symposium series 233,
(American society Washington, DC),1993.
5. Chemla D S & Zyss J (Eds), Non-linear optical properties of organic molecules
and crystals (American press, Newyork),1987
6. P.Angeli mary, S.Dhanuskodi, Cryst. Res. Technol 36,1231 (2001).
7. S.K.Kurtz, T,T.perry, J. Appl. Phys. 39,3798 (1968).
8. Balrew C and Duhlew R (1984), Application of the hard and soft acids and bases
concept to explain legend in double salt structures, J. Solid state Chemistry, Vol.
55.pp. 16.
257
VARIATIONAL ITERATION METHOD FOR BURGER EQUATION
M.Sudhalakshmi1, R.Sivakumar2 1Department of Physics, Shanmuga Industries Arts and Science College,
Tiruvannamalai District- 606601, Tamil Nadu 2Department of Physics, Pondicherry University, Pondicherry - 605 014
ABSTRACT.
The Variational iteration method (VIM) attracted much attention in the past few
years as a promising method for solving non linear differential equations. Unlike
numerical methods which provide only first or second order accurate results and
require high performance Computing facilities with a few teraflops of computing
power, variational iteration method not require any linearization procedures to solve
the PDEs under consideration and also no computing facilities are needed. Burger
equation is a well known and simple nonlinear equation in the study of fluid and
aerodynamics simulation. Hence, we applied this technique to solve the Burger
equation. The results show that this method gives reasonably accurate values
compared with analytical solution even with two iterations itself and hence it is
considered as a powerful alternative to numerical techniques where possible. It is
also observed that extending this method to solve other nonlinear PDEs, though
appears straightforward, is not easy because we have to start with an initial solution
that may be close to actual solution, which in general is not possible for practical
problems.
Key words: Variational iteration method; Burgers equation.
1. INTRODUCTION
Modern mathematics and symbol computation has posed a challenge of handling
strongly nonlinear equations which cannot be successfully dealt with by classical
methods. It is very easy to find the solutions of linear systems by means of computer.
But, it is still very difficult to solve nonlinear problems either numerically or
theoretically. The fact is various discredited methods or numerical simulations apply
iteration techniques to find their numerical solutions of nonlinear problems, all of
them are sensitive to initial solutions and difficult to obtain converged results in
strong nonlinearity. Variational iteration method (VIM) [14] is uniquely qualified to
258
address this challenge, the flexibility and adaptation provided have made the method
a strong candidate for approximate analytical solution and wide applications in
various fields. It provide physical insight into the nature of the solution of the
problem and find accurate solution among all the possible trial-functions. The
convergence VIM is systematically discussed by Tatari and Dehghan. J.H.He first
applied the variational iteration method to fractional differential equations revealing
a great success. Abbasbandy applied the variational iteration method to Riemann-
Liouville's fractional derivatives, draganescu and his colleagues to nonlinear
vibration with fractional derivative successfully applied. He applied this method to
autonomous ordinary differential systems and nonlinear equations with convolution
product nonlinearity, Abulwafa et al. to nonlinear coagulation problem with mass
loss and to nonlinear fluid flows in pipe-like domain, Ariel et al. to axisymmetrical
flow over a stretching sheet. Problems arising in Adomian Decomposition Method
can be completely eliminated by Variational Iteration Method.
2. HE'S VARIATIONAL ITERATION METHOD
He [6]-[17] has recently attracted a great deal of attention for solving easily and
efficiently a number of nonlinear functional equations. The main feature of the
proposed Variational Iteration Method [9, 29] is the solution of a mathematical
problem with linearization assumption is used as initial approximation (trial-
function), and then a more highly precise approximation at some special point can be
obtained. VIM by including all direction variables [20] called the global variation
iteration method (GVIM). By a variational approach, He's method turns the
functional equation into a recurrence sequence of functions is the exact solution. The
keystone of the VIM is a generalized Lagrange multiplier determined by stationary
conditions imposed on an appropriate correction functional.
xgxTu (1)
where T is a differential operator acts on sufficiently smooth functions u defined on
some interval. The function g is given, and defined for all x . The VIM is based on
splitting T into linear and nonlinear operators as follows:
z)y,x,g(t, Nu (u)L (u)L (u)L (u)L zyxt (2)
259
where zyxt L andL ,L,L are linear operators of z y, x,t, respectively. N is a nonlinear
operator, and z) y, x,g(t, is a known analytical function or the source inhomogeneous
function. Numerical solutions using n th approximations show the high degree of
accuracy and in most cases nu and nv the n th approximation is accurate for quite
low of )3( nn .
2.1. Correction Function. Variational iteration method [8], constructs the
correction functional as, where general Lagrange multipliers can be identified via
variational theory. The non linear term and the analytical function usually taken as
correction.
,0,0
~
1
ndssgsuNsLustutu
t
nnnn (3)
2.2. Restricted Variation. In 3 He [8]-[18] took the variations in nonlinear term,
the analytical function and sometimes the linear term are variation as restricted so as
to find the approximate Lagrange multiplier which helps in solving the equation to
get the exact solution. The variation operator on the restricted variation term leads to
zero i.e. 0~
nu . The subscript denotes n the n th-order approximation.
2.3. Stationary Condition. The extrem point of a surface ),,( yxzz where the first
differential, ),,(1 yxzz vanishes called stationary point or the extremum point of
the surface.
2.4. Lagrange Multiplier. One can enforce the constraints by applying the Lagrange
multiplier rule. Lagrange multipliers [25, 21, 20] known well in optimization and
calculus of variation, identified optimally via integration by parts. The successive
approximations 0,,1 ntxun of the solution txun ,1 will be readily obtained upon
using the Lagrangian multiplier obtained and by using any selective function 0u . The
initial values 0,xu and 0,xut are usually used for the selective zeroth
approximation 0u . Having determined, then several approximations
,0,, jtxu j can be determined. Consequently, the solution is given by nn uu lim .
Lagrange multiplier is nothing else but the retarded Green function for some
differential operators, making easier the study of the convergence of iteration
formulas.
260
3. BURGER EQUATION
Burger's equation [2, 27] is a useful model equation which governs shock wave,
acoustic transmission, traffic and aerofoil flow theory, turbulence and supersonic
flow as well as a prerequisite to the Navier-Stokes equations. It is a useful model
equation applied to complicated fluid flow problems and interesting challenge for the
control design. Numerical methods such as finite difference or characteristics
method need a large amount of computation and the effect of round-off error which
causes the loss of accuracy. Analytical methods for solving Burger's equation are
very restricted and can be used in very special cases; so they cannot be used to solve
equations of numerous realistic scenarios. He's variational iteration method is a
powerful device for solving functional equations.
3.1 ONE DIMENSIONAL BURGER EQUATION
2
2 ,,,,x
txux
txutxut
txu
(4)
with the initial condition and boundary condition
)sin()0,( xxu in , (5)
,0),1(),0( tutu 0t (6)
where , is the interval (0,1).
By VIM, correction function as,
(7)
Applying the variational operator on both sides we get
Applying He's calculus of variation
(8)
dxuxttxtxut
nttn 0
'nn1 ,)(/,u/)(,u),(
261
dxuxtt
ntt 0
'n ,)(/,u/)(1
we get the stationary conditions as,
(9)
(10)
The Lagrange multiplier can be identified as,
1)(1/ tt (11)
Substituting 11 in 7 we get,
(12)
We start with an arbitrary initial approximation that satisfies 5
(13)
Using 13 and Substituting 0n in 12
dx
xx
xxxxtxut
0
2
2
1)sin()sin()sin(sin)sin(),(
=
txtxxxtxu 21 sincossinsin, (14)
Using 13 and Substituting 1n in 12
txtxxxtxu 22 sincossinsin,
262
dtxxxxt
2
0
sincossinsin
t
xxxx0
2sincossinsin
dxxxxx
2sincossinsin
dxxxxx
t2
02
2
sincossinsin
(15)
txu ,2 txtxxx 2sincossinsin txtxx 2sincossin
dxxxxtxtxxxt
0
322222 )cos()(cossincos*sincossinsin
dxxxxx
t
0
32222 )cos()(cossincos
Using a basic trigonometric identity,
xxxx 2222 cos1sin1cossin
txu ,2 txtxxx 2sin21cossinsin
232222 cos21cossin
23 txxintxx
33333 cossin32cossin
31 txxtxx
txxtxx 32342 cossin21cossin
txtxxtx 235234 sincossin31sin
31
24223 sin21cossin2 txtxx (16)
263
We now calculate the numerical results of the solution of one dimensional Burger
equation 4 using the equation 17. The value is compared with the analytical solutions
obtained from the infinite series of Cole (1951) for 1 and 05.0 .
10
1
cosexp
sinexp2,
22
22
n
tnn
n
tnn
xnnaa
xnnatxu
(17)
Where dxxa 1
0
10 cos12exp
and 1,cos1exp2exp2 11
0
ndxxan
The error in the solution obtained by Variational Iteration Method is the absolute
difference between the analytical values and 16. The solutions are tabulated in the
tables 1, 2, 3, 4. From these tables we observe the absolute error is smaller than 710
even for second iteration. To reduce the error further, we continue with higher
iterations. In the case of ,01.0 17 is not available due to slow convergence of the
infinite series.
Table 1: Numerical results for ),(2 txu obtained by VIM method in comparison with the
analytical solution when 1 at 001.0t
x
Analytical solution VIM solution Absolute error
0.1 0.30509 0.305088779442865 -1.2206e-006
0.2 0.58057 0.580565715583992 -4.2844e-006
0.3 0.79962 0.799622134163804 2.1342e-006
0.4 0.94082 0.940816977865164 -3.0221e-006
0.5 0.99018 0.990174197811924 -5.8022e-006
0.6 0.94261 0.942608939642337 -1.0604e-006
0.7 0.80252 0.802521594140596& 1.5941e-006
0.8 0.58347 0.583465181635796 -4.8184e-006
0.9 0.30688 0.306880751049611 7.5105e-007
Table 2: Numerical results for ),(2 txu obtained by VIM method in comparison with the
264
analytical solution when 1 at 01.0t
x
Analytical solution VIM solution Absolute error
0.1 0.27324 0.273735811016050 4.9581e-004
0.2 0.52156 0.522331167664062 7.7117e-004
0.3 0.72185 0.722561260871781 7.1126e-004
0.4 0.85459 0.854983558978212 3.9356e-004
0.5 0.90571 0.905713400017763 3.4000e-006
0.6 0.86833 0.868036910800391 -2.9309e-004
0.7 0.74410 0.743686942574091 -4.1306e-004
0.8 0. 54282 0.543462924377093 -3.5708e-004
0.9 0.28700 0.286798992412058 -2.0101e-004
Table 3: Numerical results for ),(2 txu obtained by VIM method in comparison with the
analytical solution when 1 at 001.0t
x
Analytical solution VIM solution Absolute error
0.1 0.30795 0.307944996153760 -4.7762e-006
0.2 0.58601 0.586005982917996 -3.6487e-006
0.3 0.80713 0.807125933170980 -3.6985e-006
0.4 0.94966 0.949661807529539 2.0352e-006
0.5 0.99950 0.999501708362594 1.7084e-006
0.6 0.95151 0.951506106166328 -4.1215e-006
0.7 0.81011 0.810110075965496 -2.9240e-007
0.8 0.58899 0.588990131787523 -2.3658e-007
0.9 0.30979 0.309789304620123 -9.2304e-007
Table 2: Numerical results for ),(2 txu obtained by VIM method in comparison with the
analytical solution when 05.0 at 01.0t
x VIM solution Absolute error
265
Analytical solution
0.1 0.29865 0.298657507832716 7.5078e-006
0.2 0.57044 0.570450730987659 1.0731e-005
0.3 0.79034 0.790332422257759 -7.5777e-006
0.4 0.93696 0.936947206244648 -1.2794e-005
0.5 0.99460 0.994585517200631 -1.4483e-005
0.6 0.95513 0.955134884175102 4.8842e-006
0.7 0.81976 0.819765618112585 5.6181e-006
0.8 0.59988 0.599890001853205 1.0002e-005
0.9 0.31686 0.316855015336998 -4.9847e-006
4. CONCLUSION
. In this work, we have reviewed available literature, of numerical and analytical
methods on solving PDE's. We have selected one of the available analytical method
called Variational Iteration Method. We have applied VIM to solve various forms of
Burger equation. From the solutions we find that even with a very few iterations one
can get reasonably accurate solutions as we seen in the Tables 1 to 4. This indicates
that VIM is a powerful technique to find analytical solutions of PDE's.
5. BIBLIOGRAPHY
[1] R. Noorzad, A.T. Poor, M. Omidvar, Variational iteration method and homotopy-
perturbation method for solving Burgers equation in fluid dynamics. J. Applied Sci. 8
(2008) 373393 .
[2] H. Bateman, Some recent researches on the motion of fluids. Monthly Weather
Rev. 43 (1915) 170163 .
[3] J.D. Cole, On a quasi-linear parabolic equation occurring in aerodynamics. Qurat.
Appl. Math. Model 9 (1951) .236225
[4] D. Mitra, Studies of Static and Dynamic Multiscaling in Turbulence. Physica A 318 (2003) 186179 .
[5] X. Wu, J. Zhang, Artificial boundary method for two-dimensional Burger's equation. Computer and Mathematics with Application 56 (2008) 256242 .
266
[6] J.H. He, A new approach to nonlinear partial differential equations. Commun. Nonlinear Sci. Numer. Simul. 2 (1997) 235230 .
[7] J.H. He, Variational iteration method for delay differential equations. Commun. Nonlinear Sci. Numer. Simul 2 (1997) 236235 .
[8] J.H. He, Approxmiate analytical solution for seepage flow with fractional derivatives in porous media. Comput. Methods Appl. Mech. Eng 167 (1998) 6857 .
[9] J.H. He, A coupling method of a homotopy technique and a perturbation technique for non-linear problems. Int. J. Non-linear Mech. 35 (2000) 4337 .
[10] J.H. He, A new perturbation technique which is also valid for large parameters. J. Sound Vibration 229 (2000).
[11] J.H. He, Variational iteration method is a kind of nonlinear analytical technique: some examples. Int. J. Non-linear Mech,. 34 (1999) 708699 .
[12] J.H. He, Some asymptotics methods for strongly nonlinear equations. Int. J. Modern Phys. 20 (2006) 1141--1199.
[13] J.H. He, Variational iteration method - Some resent results and new interpretations. J. Comput. Appl. Math. 207 (2007) 173 .
[14] J.H. He, X.H. Wu, Variational iteration method: New development and applications. Computers and Mathematics with Application 54 (2007) 894881 .
[15] J.H. He,G.w. Wu,F. Austin, The VIM which should be followed. Non-linear Science LettersA- Mathematics, physics & mechanics. 35 (2010).
[16] Sh.Q. Wang, J.H. He, Variational iteration method for solving integro-differential equations. Phys. Lett. A 367 (2007) 191188 .
[17] J.H. He, Variational approach for nonlinear oscillators. Chaos, Solitons and Fractals 34 (2007) 14391430 .
[18] S.J. Liao, An approximate solution technique not depending on small parameters; a special example. Int. J. Non-Linear Mech. 30 (1995) 380371 .
[19] M. Mamode, Variational iteration method and initial-value problems Appl. Math. Comput. 215 (2009) 282276 .
[20] W.X. Qian, Y.H. Ye, J. Chen, L.F. Mo, He's iteration formulation for solving non-linear Algebraic equations. J. Phys. 96 (2008).
[21] S. Pamuk, A Review of some recent results for the approximate analytical solutions of nonlinear differential equations. Hindawi publishing corporation (2009).
267
[22] G. Adomian, Solving Frontier Problems of Physics: The Decomposition
Method. kluwer (1994).
[23] D. Altintan, O. Ugur, Variational iteration method for Sturm-Liouville
differential equations. Computers and Mathematics with Applications. 58
(2009) 328322 .
[25] S.A.E. Wakil, M.A. Abdou, New applications of variational iteration method
using Adomian polynomials. Non-Linear Dynamics 52 (2008) 4941 .
[26] A.M. Wazwaz, The variational iteration method: A reliable analytic tool for
solving linear and nonlinear wave equations. Computers and Mathematics with
Applications 54 (2007) 932926 .
[27] J.A. Atwell, J.T. Borggaard, B.B. KING, Reduced Order Controllers for
Burgers Equation with a Nonlinear Observer. Int. J. Appl. Math. Comput. Sci. 11
(2001) 13301311 .
[28] S.M. Goh , M.S.M. Noorani , I. Hashim, A new application of variational
iteration method for the chaotic Rossler system. Chaos, Solitons and Fractals 42
(2009) 16101604 .
[29] A.M. Kawala, Numerical solution for Ito coupled systems. Acta Appl. Math.106
(2009) 335325 .
[31] A. Ghorbani , J.S. Nadjafi, An effective modification of He's variational
iteration method. Nonlinear Analysis: Real World Applications. 10 (2009)
28332828 .
[32] B.D.Hahn, Essential Matlab for Scientists. Elsevier 2002.
[33] J. Zhang, G. Yan, Lattice Boltzmann method for one and two-dimensional
Burgers equation. Physica A 387 (2008), 47864771 .
268
GROWTH AND CHARACTERIZATION OF L-ALANINE MIXED
BISTHIOUREA CADMIUM BROMIDE(LABTCB) CRYSTAL
*A. Maniselvan and 1T.Kubendiran
*Asst. professor, PG& Research Department of physics, Shanmuga Industries Arts and Science College, Tiruvannamalai-606 601
1Asst. professor, PG& Research Department of physics, Govt. Arts college
Tiruvannamalai-606 603
ABSTRACT
L-alanine mixed bisthioureacadmium bromide (LABTCB) single crystal has
been grown by slow evaporation method.The grown crystal has been characterized
by single crystal XRD analysis, powder XRDanalysis, FTIR analysis, UV-Vis-NIR
analysis and SHG studies. XRD analysis confirms thecrystalline nature of the
materials. The presence of various functional groups present in LABTCB crystal has
been confirmed by FTIR analysis. The UV-Vis-NIRspectrum shows the transmission
characteristics of the crystals. The SHG study depicts thenonlinear optical efficiency
of the crystal.
KEY WORDS: Solution growth, FTIR, XRD, SHD..,
INTRODUCTION:
Non-linear optics is a very useful technology because it extends the
usefulness of lasers by increasing the number of wavelength available both longer
and Shorter than the original can be produced by non-linear optics.
A versatile and highly efficient non-linear optical frequency conversion
material is of vital importance for many applications in the field of photonics and
optoelectronics. The interest of the researchers on NLO crystal is not confined just to
their NLO properties. Among these materials show large non-linear linearity, low
angular sensitivity and good mechanical hardness.
NLO crystals has emerged as one of the most attractive field of current
research in view of its vital applications in areas like optical modulation, optical
269
switching, optical logic frequency shifting and optical data storage for the
developing technologies in telecommunication and inefficient signal processing[1-5].
The search for new, very efficient non-linear materials, for fast and optimum
processing of optical signals has become very important, because of development of
optical fiber communication, laser based imaging and remote sensing etc. In many of
the organic NLO materials there is a solid framework of conjugated electronics
along with weak Vander Waals and hydrogen bonds which are responsible for their
NLO properties.
4 techniques at room temperature. The grown crystals were subjected to various
characterization studies like structure analyze by single and powder diffraction and
the presence of functional groups in the sample was investigated by Fourier
transform infrared spectrometer. The linear and non-linear optical property were
carried by UV-VIS absorption spectrometer and Kurtz and Perry Powder technique.
The dielectric behavior was analyzed. The photo conducting nature of the crystal has
been carried out.
Growth by Slow evaporation method
LABTCB crystal is synthesized by dissolving AR grade thiourea and AR
grade cadmium bromide in the molar ratio 2:1 in distilled water. The saturated
solution of cadmium bromide was slowly added to the saturated solution of
thiourea.Then was added drop by drop . This was stirred well to get a clear solution.
Pure BTCB crystal was synthesized according to the reaction:
2[CS (NH2)2] + CdBr2 → Cd [CS (NH2)2]2 Br2
The solution was purified by repeated filtration. The saturated solution was
kept in a beaker covered with polythene paper. For slow evaporation 6 or 7 holes
were made in the polythene paper. Then the solution was left undisturbed in a
constant temperature bath (CTB) kept at a temperature of 35 °C with an accuracy of
± 0.1° C. As a result of slow evaporation, after 75 days colorless and transparent
pure BTCB crystals were obtained.
270
Single Crystal X-ray diffraction analysis of L-Alanine mixed BTCB crystals
The single crystal XRD analysis of L-Alanine mixed BTCB crystal was
carried out using ENRAF NONIUS CAD 4 single crystal X-ray diffractometer with
Mokα (λ=0.071073Å) radiation. From the XRD data, it was observed that the L-
Alanine mixed BTCB crystal belongs to tetragonal crystal system and its lattice
parameters are found to be a=9.234Å b=13.747Å c=13.75Å.
Powder X-ray diffraction analysis of L-Alanine mixed BTCB crystals
The grown crystal of L-Alanine mixed BTCB crystals were crushed into fine
powder and powder X-ray diffraction analysis have been carried out using Rich
Seifert X-ray diffractometer.
Figure: Powder XRD pattern of LABTCB crystal
The sample was subjected to intense X-ray of wavelength 1.5406 Å (CuKα) at
a scan speed of 1° per minute to obtain lattice parameters. The recorded patternwas
shown in Figure. The observed diffraction pattern has been indexed by Reitveld
index software package. The lattice parameters have been calculated by Reitveld unit
cell software package. It is found that there is a close agreement with values obtained
by single crystal. The lattice parameters are found to be, a=9.2143Å, b=13.7394Å
and c=13.7533Å.
271
FTIR spectrum analysisof L-Alanine mixed BTCB crystals
The FTIR spectroscopy studies were used to analyze the presence of
functional groups in synthesized compound. The FTIR spectra LABTCB was
recorded using Perkin Elmer spectrometer model spectrum RX1 using KBr pellet
technique in the range 4000 - 400 cm-1 and shown in Fig. The characteristic
vibrational frequencies of the functional groups of L alanine mixed BTCB have been
compared with thiourea. The comparison of characteristic vibrational frequencies has
been tabulated in Table: 1
Figure: FTIR spectrum of LABTCB crystal.
NH stretching vibration of thiourea was observed at 3376 cm-1. The same vibration
wasobserved at 3395 cm-1 in LABTCB crystal. An NCN symmetric bending
vibration was observed in pure thiourea at 494 cm-1 and the same vibration was
observed in LABTCBat 471 cm-1. C=S asymmetric stretching vibration wasobserved
in pure thiourea near 1417 cm-1, the same vibration was also observed in LABTCB
at 1392 cm-1.
272
Table: 1 Vibrational assignments of thiourea and LABTCB crystals
In the FTIR spectra, the NH stretching vibrational bands of NH2 asymmetric
stretching were
observed around 3280
cm-1, 3281 cm-1 and
3285 cm-1. The NH2
symmetric stretching
vibrations are observed
around 3167 cm-1, 3194
cm-1 and 3197 cm-1.
These bands were
shifted to higher wave
number region when compared to that of the free ligand. This shift may be due to the
S.No BTCB
(cm-1)
LABTCB
(cm-1) ASSIGNMENT
1 3376 3395 NH Stretching
2 3280 3285 NH2 asymmetric stretching
3 3167 3197 NH2 asymmetric stretching
4 1627 1619 NH bending
5 1472 1490 CN asymmetric stretching
6 1417 1392 CS asymmetric stretching
7 1089 1089 CN symmetric stretching
8 740 709 CS symmetric stretching
9 494 471 N-C=N symmetric bending
273
increase in the polar character of thiourea molecule because of the formation of
S→M bonds in L-alanine mixed BTCB complex. The band observed around
1627 cm-1 corresponds to NH bending vibration of thiourea. The same vibration was
observed at 1619 cm-1 in LABTCB. The bands observed around 1490 cm-1 were
identified as the C-N asymmetric stretching vibration.The bands observed around
709 cm-1 corresponds to C=S stretching vibration. The bands for CN symmetric
stretching vibration in the grown crystal were observed around 1089 cm-1. The
standard IR bands of thiourea and LABTCB are compared along with their
assignments and are presented in Table1. It is found that the CN stretching (1089 and
1472 cm-1) bands of thiourea are shifted to higher frequencies for LABTCB.Also the
CS stretching bands of thiourea (1417 and 740 cm-1) are shifted to lower frequencies
in LABTCB. These results reveal that the metals coordinate with thiourea through
sulphur. The slight variation in the observed frequencies of LABTCB is due to the
presence of L-alanine.
V-VIS spectral analysis of LABTCB crystal
Figure shows UV-Vis-NIR spectrum of LABTCB crystal
The absorption and transmission spectrum of LABTCB was recordedusing
UV-Vis-NIR spectrophotometer in the range from 190nm to 1100nm using Cary 500
scan UV-Vis-NIR spectrometer and it is shown in Fig. The crystal shows a good
transmittance in the visible region which enables it to be a good material for
optoelectronic applications. As observed in the spectrum, LABTCB was transparent
in the region from 259 nm to 1100 nm. The lower cut off wavelength for LABTCB
is found at 259 nm. The wide range of transparency suggests that the crystals are
good candidates for nonlinear optical applications. The shift of lower
cutoffwavelength in UV region is due to mixing of L-alanine and is desirable for
optoelectronic application.
274
Second Harmonic GenerationEfficiency measurement
The second harmonic generation test was carried out by classical powder
method developed by Kurtz and Perry. It is an important and popular tool to evaluate
the conversion efficiency of NLO materials. The fundamental beam of 1064 nm
from Q switched Nd: YAG laser was used to test the second harmonic generation
(SHG) property of LABTCB crystal. Pulse energy 2.9 mJ/pulse and pulse width 8 ns
with a repetition rate of 10 Hz were used. The photo multiplier tube (Hamamatsu
R2059) was used as a detector and 90 degree geometry was employed. The input
laser beam was passed through an IR detector and then directed on the
microcrystalline powdered sample packed in a capillary tube. TheSHG signal
generated in the sample was confirmed from emission of green radiation from the
sample. The nonlinear optical (NLO) efficiency of LABTCB is 87 mV. The green
light output was detected by a photomultiplier tube. KDP and urea crystals were
powdered to the identical size and were used as reference materials in the SHG
measurement. The SHG relative efficiency of LABTCB crystal was found to be
7.9times higher than that of KDP and 0.836 times that of urea Table 3.
Table: 2 Comparative study of NLO efficiency
Crystal NLO efficiency
(in mV)
LABTCB 87
KDP 11
Urea 104
275
CONCLUSION
The potential semiorganic NLO crystal LABTCB was grown by slow
evaporation method. The grown crystals were characterized by single crystal XRD
analysis, powder XRD analysis, FTIR analysis, UV-Vis-NIR analysis and SHG
studies. The XRD analysis confirms the crystalline nature of the materials. The
presence of various functional groups present in LABTCB crystal has been
confirmed by FTIR analysis. The UV-Vis-NIR spectrum of grown crystal shows that
the crystal is transparent in the wavelength region from 269nm to 1100nm. The SHG
efficiency of the grown LABTCB crystal was 7.9 times greater than the KDP
crystals. Owing to all these properties LABTCB could be a promising material for
NLO applications.
REFERENCES:
1. Nalwa H S & Miyata S,Non-linear optics of organic Molecules and polymers
(CRC press,Newyork)1997.
2. Prasad P N & Willams DJ, Introduction to Non-linear optical effects in
Organic molecules and polymersb(Wiley, Newyork),1991.
3. Hann R A & Bloor D (Eds), Organic materials for Non-linear optics, (The
Royal society of chemistry),1989.
4. Badan J,Hiere R,Perigand A, et al (Ed), Non-linear optical properities of
organic molecules and polymeric materials, American chemicals symposium
series 233, (American society Washington, DC),1993.
5. Chemla D S & Zyss J (Eds), Non-linear optical properties of organic
molecules and crystals (American press, Newyork),1987
6. P.Angeli mary, S.Dhanuskodi, Cryst. Res. Technol 36,1231 (2001).
7. S.K.Kurtz, T,T.perry, J. Appl. Phys. 39,3798 (1968).
276
ULTRASONIC STUDIES ON THE EFFECT OF DMSO AND DMF ON
THE MICELLIZATION OF LITHIUM DODECYL SULPHATE
IN AQUEOUS SOLUTIONS
G. Lakshiminarayanan1 and R. Kumaresan2
1,2Department of Physics, Shanmuga Industries Arts and Science College,Thiruvannamalai. ABSTRACT
Ultrasonic velocity, density and viscosity studies have been carried out in
aqueous solutions of lithium dodecyl sulphate (LDS) and in aqueous solutions of
LDS containing 5-20% V/V of dimethyl sulphaoxide (DMSO), dimethyl formamide
(DMF). These studies are carried out in LDS concentration of 5mM to 14mM at a
fixed frequency of 2MHz and at a fixed temperature of 303.15K. The variation of
ultrasonic velocity in aqueous solutions of LDS containing 5-20% V/V of DMSO
and DMF with LDS concentration exhibiting a break at critical micelle concentration
(CMC). The ultrasonic velocity, adiabatic compressibility, free length, free volume
and internal pressure also exhibiting a break at CMC similar to velocity curve. The
results are discussed in terms of formation of LDS micelles through hydrophobic
interaction and hydrogen bonding.
INTRODUCTION
Molecular interaction in liquid mixtures has been the subject of numerous
investigation in recent past years [1-6]. The system shows a wide verity of physical
properties. Resent researchers have studied the interaction of lithium dodecyl
sulphate (LDS) with aqueous solutions in ultrasonic techniques [7]. But the effect of
aprotic solvent on LDS is scandy. The aim our present investigation is to determine
ultrasonic studies on the effect of DMSO and DMF on the micellization of
lithium dodecyl sulphate in aqueous solutions at fixed frequency of 2 MHz and
fixed temperature of 303.15 k. The results are interpreted in terms of formation of
LDS micelles in the solutions.
MATERIALS AND METHODS
The lithium dodecyl sulphate (LDS) used in the present study are of
AR/BDH grade purchased from SD-fine chemicals Ltd., India and they are used as
such without further purification. The solvents used namely DMO and DMF are of
spectroscopic grade. Triply distilled deionised water is used for preparing the
277
solutions of LDS. Ultrasonic velocity studies are carried out at a fixed frequency of 2
MHz in the lithium dodecyl sulphate concentration range of 5mM to 14mM.
Ultrasonic velocity is measured using a Digital Ultrasonic Velocity meter (Model
VCT-70A, Vi-Microsystems Pvt. Ltd., Chennai, India) at a fixed temperature at
303.15K by circulating water from a thermostatically controlled water bath and the
temperature being maintained to an accuracy of ±0.1oC. The accuracy in
measurement of velocity and absorption is ±2 parts in 105 and 3% respectively.
Shear viscosity and density of aqueous solutions of lithium dodecyl sulphate
containing 5-20% V/V of DMSO and DMF are determined using an Oswald’s
viscometer and a graduated dilatometer respectively. The accuracy in measurement
of density and viscosity is ±2 parts in 104 and ± 0.1% respectively. From the
measured values of ultrasonic velocity, density and viscosity, the various other
parameters such as adiabatic compressibility (βs), intermolecular free length (Lf),
free volume (Vf ) and internal pressure (Пi) are calculated using standard formulae.
COMPUTATIONS OF PARAMETERS
Adiabatic compressibility (βs), intermolecular free length (Lf), free volume
(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),
respectively.
βs = 1/C2ρ (1)
Lf = KT βs 1/2 (2)
Vf = (M C / K η)3/2 (3)
πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)
where, c is ucltrasonic velocity, ρ is density, KT is temperature dependant constant,
M is effective molecular weight, K is constant for liquids, b is constant, T is
temperature.
RESULT AND DISCUSSIONS
From the measured values of density, ultrasonic velocity and viscosity,
the other parameters such as adiabatic compressibility, free length, free volume and
internal pressure were computed and shown in graphically in figures (1-12).The
variations of ultrasonic velocity against concentration of lithium dodecyl sulphate
278
(LDS) in aqueous solution are given in Figs. 1 & 2. The measured ultrasonic
velocity increases with increasing concentration of lithium dodecyl sulphate in
aqueous solutions and exhibits sharp break at a particular concentration is known as
Critical Micellar Concentration (CMC), which is confirmed by Chanchal das et al
[7]. The increase in ultrasonic velocity before CMC is due to the sulphate ions
making hydrogen bond with water molecules. The micelle formation in aqueous
solution of lithium dodecyl sulphate and higher aggregation leads to increase in
velocity after CMC.
The measured ultrasonic velocity increases with increasing
concentration of lithium dodecyl sulphate in aqueous – aprotic solvent (5-20%V/V
of DMSO and DMF) mixtures of solution and exhibits sharp break at a particular
concentration of lithium dodecyl sulphate (i.e.)., CMC as shown in Fig 1 & 2. The
increase in ultrasonic velocity is due to the aprotic solvents act as a structure breaker
in aqueous lithium dodecyl sulphate. Lithium ions are restricting the mobility of the
water molecules. This leads to increase of ultrasonic velocity for before CMC. The
micelle formation in aqueous-aprotic solution of lithium dodecyl sulphate and higher
aggregation leads to increase in velocity before and after CMC of solution. In
addition to dipole moment of DMSO in the solution also contributes increase in
ultrasonic velocity. The velocity observed in aqueous-aprotic solvent at particular
compositions (volume by volume) in the order:
Velocity of DMSO mixture > Velocity of DMF mixture.
From the figures 1 & 2, it is observed that when the 5% V/V of DMSO is
added to the aqueous solution of lithium dodecyl sulphate , the CMC of aqueous
solution of lithium dodecyl sulphate shifted towards the higher concentration side
(8.5 mM). This is due to the lowering of the average dielectric constant of the
medium because of the dielectric constant of water is greater than DMSO.
Similarly, when the 10-20% V/V of DMSO is added to the aqueous solution
of lithium dodecyl sulphate , the CMC of aqueous solution of lithium dodecyl
sulphate shifted towards the higher concentration side in the order of (9.0 mM), (9.4
mM), (9.8 mM), respectively.
All the above explanation is offered for the additive of DMF of various
compositions except the breaking value of CMC. Here, the observed value of CMC
279
is 9.0 mM, 9.4 mM, 9.8 mM and 10.4 mM by addition of 5% of DMF, 10% of
DMF, 15% of DMF and 20% of DMF, respectively. This is due to the difference in
dielectric constant of the DMSO and DMF in these solutions.
Adiabatic compressibility, free length and free volume, internal pressure
studies are supported the ultrasonic velocity studies in aqueous and aqueous aprotic
solvents mixtures.
CONCLUSION
In the present study, the ultrasonic velocity, density, viscosity and internal
pressure increases whereas adiabatic compressibility, free length and free volume
decreases with increasing concentration of lithium dodecyl sulphate in aqueous and
aqueous – aprotic solvent (DMSO & DMF) mixtures. Ultrasonic velocity of DMSO
is slightly higher than DMF for all aqueous and aqueous – aprotic solvent mixtures
because of due to their difference in dipole moment.
The CMC values are obtained in aqueous and aqueous – aprotic solvent
(DMSO and DMF) mixtures of various compositions of concentration of lithium
dodecyl sulphate solutions. The higher CMC values in aqueous – DMF mixtures for
various composition compared to aqueous – DMSO mixtures of various composition
of concentration of lithium dodecyl sulphate. This is due to the average dielectric
constant modification in aqueous – aprotic solvent (DMSO & DMF) mixtures of
lithium dodecyl sulphate.
Figure-1 Figure-2
0.004 0.006 0.008 0.010 0.012 0.014
14951500150515101515152015251530153515401545155015551560156515701575158015851590
Ultr
ason
ic V
eloc
ity(C
) m s
-1
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS
0.004 0.006 0.008 0.010 0.012 0.014
14951500150515101515152015251530153515401545155015551560156515701575
Ultr
ason
ic V
eloc
ity(C
)m s
-1
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS
280
Figure-3 Figure-4
Figure-5 Figure-6
Figure-7 Figure-8
0.004 0.006 0.008 0.010 0.012 0.014
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5Vi
scoc
ity()
10-4N
s m
-2
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS 0.004 0.006 0.008 0.010 0.012 0.014
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
Visc
ocity
() 1
0-4N
s m
-2
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+ 5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS
0.004 0.006 0.008 0.010 0.012 0.014
3.9
4.0
4.1
4.2
4.3
4.4
4.5
Adi
abat
ic c
ompr
essi
bilit
y( )1
0-10 m
2 N-1
Molar Concetration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS
0.004 0.006 0.008 0.010 0.012 0.014
3.95
4.00
4.05
4.10
4.15
4.20
4.25
4.30
4.35
4.40
4.45
4.50
Adia
batic
Com
pres
sibi
lity(
) 10-1
0 m2 N
-1
Molar concentration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS
0.004 0.006 0.008 0.010 0.012 0.0140.390
0.395
0.400
0.405
0.410
0.415
0.420
0.425
Free
Len
gth(
L f) 10-1
0 m
Molar Concetration of Lithium Dodceyl Sulphate
Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS
0.004 0.006 0.008 0.010 0.012 0.0140.395
0.400
0.405
0.410
0.415
0.420
0.425
Free
Len
gth(
L f) 10
-10 m
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS
281
Figure-9 Figure-10
Figure-11 Figure-12
References
1) P.G.T. Fogg, J. Chem. Soc., 83, 117 (1958).
2) J. Millar and A.J. Parker J. Am. Chem. Soc., 83, 117 (1961).
3) D.S. Allam and W. N. Lee, J. Chem. Soc., 6049 (1964).
4) S. Nakamura and S. Meiboom, J. Chem. Soc., 89, 1765 (1967).
5) K. Ramabrahaman, Ind.J.Pure.Appl.Phys.6,75 (1968)
6) C.V. Chaturvedi and S. Prakash, Ind. J.Chem.,10,669 (1972)
7) Chanchal Das & Dilip K Hazra Indian J. CHEM vol. 44A,1793(2005).
0.004 0.006 0.008 0.010 0.012 0.0140.80
0.850.90
0.951.001.05
1.101.151.201.25
1.301.35
1.401.451.50
1.551.60
Free
Vol
ume(
V) 1
0-6 m
Molar Concentration of Lithium Dodceyl Sulphate
Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS
0.004 0.006 0.008 0.010 0.012 0.014
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
1.0771.0441.0110.9800.9500.9240.9080.9030.8960.891
Free
Vol
ume(
L f) 10
-6 m
-3
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+ 5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS
0.004 0.006 0.008 0.010 0.012 0.0148.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
Inte
rnal
Pre
ssur
e() 1
03 pas
cal
Molar Concentration of Lithium Dodecyl Sulphate
Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS
0.004 0.006 0.008 0.010 0.012 0.0148.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5In
tern
al P
ress
ure(
) 103 p
asca
l
Molar Concentration of Lithium Dodcecyl Sulphate
Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS
282
GROWTH AND CHARACTERIZATION OF BISTHIOUREA MANGANESE
SULPHATE SINGLE CRYSTAL BY SLOW EVAPORATION METHOD
H.POORNIMA
Research Scholar, Department of Physics, Shanmuga Industries Arts & Science College
Tiruvannamalai – 606 601.
ABSTRACT
Bisthiourea Manganese Sulphate crystals were grown by slow evaporation
technique. The grown crystals were characterized by powder x-ray diffraction, it is
confirmed that the synthesized material has characterized nature. The FTIR
spectrosocopic studies were effectively used to identify the functional groups present
in synthesized compound and the molecular structure. From UV-Vis Spectral
Analysis the crystal has a 80% transmission in the entire visible region. The thermal
studied by TGA and DTA techniques were confirms the decomposition of the
sample around 6000C.
1.Introduction
Generally Researchers grow crystals for two main reasons, to understand how
crystals grow (aesthetic) and for the utility (scientific or technological applications of
the grown crystals); for either of these, one must evaluate the quality of the grown
crystals (structural simplicity, symmetry and purity). In recent years, several studies
deal with organic, inorganic and semiorganic molecules and materials due to the
increasing need for cheap and easily processable materials for photonics
applications. Like many metal sulphates, manganese sulphate forms a variety of
hydrates. Non linear optics plays a major role in emerging photonic and
optoelectronics technologies. New non linear optical frequency conversion materials
have a significant impact on laser technology and optical data storage. Thiourea is an
interesting inorganic matrix modifier due to its large dipole moment and its ability to
form an extensive network of hydrogen bonds. It belongs to the orthorhombic crystal
system. However, most of the thiourea complexes crystallize in centro symmetric
form at room temperature. In this present work, manganese sulphate and bisthiourea
crystals were synthesized and characterized by X- ray powder diffract (XRD) ,
283
Fourier Transform Infrared (FTIR), UV- Visible study, Differential and
thermogravimetric analysis (TGA/DTA) and Microhardness techniques.
2.Materials and methods
The BTMS salt was synthesized by dissolving thiourea and manganese sulphate
in molar ratio 2:1 in triple distilled water. The manganese sulphate solution was
added into the thiourea solution. White crystalline salt was formed at the bottom of
the container according to the following reaction.
2 [CS (NH2)2 ] MnSO4 . H2O Mn [CS ( NH2)2 ]2 SO4 H2O
BTMS crystals were grown at room temperature by slow evaporation technique
by dissolving 6g of Manganese sulphate and 19.2g of Thiourea in 100 ml of triple
distilled water under magnetic stirring. The temperature was maintained around
35°C to avoid any decomposition of element from the compound. The resulting
supersaturated solution was filtered for three times using whatmann filter paper. This
filtered solution was poured into Petri dish and it was kept under the observation for
slow evaporation at room temperature.
After a period of 20 days seed crystals were obtained. The photograph of the grown
crystal of BTMS is shown in fig.1.
Fig.1. Photograph of Grown BTMS crystal
X-ray powder diffraction was performed using cu kα radiation (λ=1.54060A0)
to identify the lattice parameters. Fourier transform infrared (FTIR) spectrum of
BTMS crystal was recorded in the range 400–4000 cm-1. The optical absorption
spectra of UCA crystals were recorded in the range of 190 – 1100 nm using Elico SL
218 double beam UV- visible spectrophotometer. Thermal stability and
physiochemical changes of the sample were analyzed by recording the TGA and
DTA spectra in nitrogen atmosphere. The mechanical property of BTMS crystal was
studied by Vickers hardness test.
284
3.Result and discussion
3.1 Powder X-ray diffraction analysis
X-ray powder diffraction analysis of BTMS crystal was carried using X-ray
diffractrometer. The sample was scanned over the range 10 to 700 at a scan rate of
10/min. The indexed powder XRD pattern of the grown crystal (BTMS) is shown in
fig.2. The X-ray diffractometer shows many diffraction peaks. From the sharpness of
the peaks it was conformed that the synthesized material has crystalline nature. From
the result it is observed that the crystal belongs to orthorhombic system with the
following cell dimensions. a=7.6212 Ao ; b=8.5427 Ao ; c=5.5019 Ao and cell
volume V=358.202 A3.
Fig.2. Powder X-ray diffraction analysis of BTMS
3.2 FTIR studies
The FTIR spectroscopic studies were effectively used to identify the functional
groups present in synthesized compound and to determine the molecular structure.
The functional groups of BTMS are confirmed by recording the FTIR spectrum in
the range of 4000-400 cm-1. The Fourier Transform Infrared (FTIR) spectrum of
BTMS is shown in Fig.3. The different functional group of this material are listed in
Table-2. The absorption observed at 3390.24 cm-1 in the spectrum of BTMS
corresponding to the N-H stretching vibration. The vibration observed at 1588.09
cm-1 in the FTIR spectrum is due to N-H bending. . The absorption observed at
3018.05 cm-1 indicates the presence of C-H stretching vibration. The vibration
observed at (872.631 and 727.996) cm-1 indicates the presence of C-H bending.
285
Fig.3. FTIR – Spectral analysis of BTMS
3.3 UV-absorption studies
The optical absorption spectrum of BTMS is shown in Fig.4. The optical
transmittance range and transparency cut off are important in optical applications.
From the UV absorption spectrum, it is evident that BTMS crystal has UV cut off
wavelength at 398 nm, which is an advantage in semi organic non linear optical
materials over their inorganic counterparts. It is well known that an efficient NLO
crystal has an optical transparency lower cut-off wavelength between 200 and 400
nm.
Fig.4. UV-Vis spectral analysis
of BTMS
3.4 Thermal analysis
The thermal stability and physiochemical changes of BTMS crystal were analyzed
by recording the TG–DTA spectrum as shown in Figure 5 & 6. It reveals that BTMS
is thermally stable upto 192°C and after this the sample undergoes appreciable
weight loss. The change in weight loss confirms the decomposing nature of BTMS
sample. The DTA spectrum confirms the melting point of the sample through a sharp
exothermic peak at 185°C. Moreover, the exothermic peak at 242°C reveals the
286
volatile nature of the sample. After that no sharp peak was observed, which confirms
that the material is thermally stable upto 242°C.
Fig.5. TGA Spectral
analysis of BTMS
Fig.6. DTA Spectral
analysis of BTMS
3.5 Vicker’s Micro hardness study
Hardness is a measure of materials resistance to localized plastic deformation. It
plays a key role in device fabrication. Transparent crystals free from cracks were
selected for micro harness measurements. The mechanical property of BTMS crystal
was studied by Vickers hardness test. The applied loads were 10, 25, 50 and 100
grams. The measurement was done at different points on the crystal surface and the
average value was taken as Hv for a given load.
The Vicker’s micro hardness was calculated using the relation
Hv = (1.8544*P)/d2 kg/mm2
Where, Hv is the Vickers micro hardness number, P - is the applied load and d- is the
diagonal length of the indentation impression. The calculated Vickers hardness
values for BTMS crystals as a function of load is shown in figure.7. For BTMS the
maximum hardness 0.080 kg/mm2 is observed for the load 100g. It is concluded that
the sample are materials.
287
Fig.7.Hardness number (Hv) Vs load (P) of BTMS crystal
4. Conclution
Good quality of BTMS crystal is grown by slow evaporation solution growth
method at room temperature. The crystal structure was confirmed by powder X-ray
diffraction study. The presence of various functional groups in the crystal have been
confirmed by using FTIR analysis. UV-Vis study showed that the grown crystal have
good optical transparency. The TG/DTA values of the crystal were determined the
melting point of the grown crystal and finally the Vickers microhardness studies
have been carried out.
References
1. Jiang,M.H.,Fang,q.(1999).advance materials
2. Ram S,J Magn Magn Matter,80 (1989)
3. Sing p, Babber V K, Razton A, Goel T C, Srivastsava I C, Indian J Appl
physics 42 (2004)
4. Saima J,Gruokova A, Papanova M.J Elect Eng 56 (2005)
5. L. Bellamy, The Infrared Spectra of Complex Molecules; Wiley: New York,
1958
6. Laura Cecilia Bichara, Hernan Enrique Lanus, Evelina Gloria Ferrer, Monica
Beatriz Gramajo, Silvia Antonia Brandan, Advan. Phys. Chem., 2011
7. Y. Le Fur, R. Masse, M.Z. Cherkaoui, J.F. Nicoud, Z. Kristallogr. 1993
8. S.M. RaviKumar, N.Melikechi, S.Selvakumar, P.Sagayaraj, J. Cryst. Growth,
2009
288
Growth and physicochemical properties of a new semiorganic nonlinear optical
material thiourea potassium hydrogen phthalate for NLO applications
A.Anbarasi1, R.Srineevasan2, M. Packiyaraj3 and S.M.Ravi Kumar2*
1Department of Physics, Periyar Government Arts College, Cuddalore 2PG & Research Department of Physics, Government Arts College, Tiruvannamalai
3Department of Physics, S.K.P. Engineering College, Tiruvannamalai
ABSTRACT
Thiourea potassium hydrogen phthalate (TKHP), a semiorganic nonlinear
optical single crystal is grown by slow evaporation solution growth technique at
room temperature. The Single crystal XRD reveals that the grown crystal is an
orthorhombic system. UV–visible NIR spectral study confirms the transmission
band of 100% in the range 200 – 900 nm with enhanced lower cutoff wavelength.
Thermal stability of TKHP was found to be 305.1°C. The second harmonic
generation (SHG) efficiency of TKHP is observed by the Kurtz powder technique.
1. Introduction
In recent years semiorganic complexes have attracted the researcher owing to
their applications in second and higher harmonic generations, optical bistability,
laser remote sensing, optical disc data storage, laser driven fusion, medical and
spectroscopic image processing, color display and optical communication [1,2].
Due to lack of extended π-electron delocalization and hence moderate optical
nonlinearity, low laser damage threshold, low optical transparency, lack of quality
and bulk size are the major limitations in organic nonlinear optical (NLO) crystals.
Hence, the research scientist focusing on new kind of crystals called semiorganic
crystal. In semiorganic, stoichiometric bond is between inorganic and organic
molecules gives the advantage of combined properties such as high optical
nonlinearity, extended transparency region-down to UV, promising crystal growth
characteristics, chemical inertness and good mechanical hardness [3]. To get the
strong mechanical and high thermal stabilities in semiorganics, cation of hydrogen
bonded nonlinear organic molecules are linked to the anion of inorganic molecules
as an acid–base interaction [4]. Highly delocalized π-electrons induces molecular
charge transfer in semiorganics, which make π-electrons easily move between
electron donor and electron acceptor groups on opposite sides of the molecule [5,6].
289
Noncentrosymmetric potassium hydrogen phthalate semiorganic crystal (KHP) is a
mono-potassium salt of phthalic acid, widely used in the field of X-ray spectroscopy
as monochromator, substrate for the deposition of thin films organic NLO materials
and analyzer with optical, piezoelectric and elastic properties (7-10). KHP is
slightly acidic, dissociates completely in water, giving the potassium cation (K+)
and hydrogen phthalate anion (HP−). Paring of dipole moment in parallel fashion of
potassium acid phthalate is established by the bonding energy present in the
hydrogen bonds linkage between acid–base interactions and hence enhanced value
of SHG activity reported [11–14].
Thiourea, less extensively delocalized organic and coplanar in structure,
exhibit mesomeric effects which are responsible for second harmonic generation
(SHG) in the blue-near-UV regions [15]. Thiourea complexes show high optical
nonlinearity with flexibility and physical hardness like organic and inorganic
materials respectively. In the present study, growth of thiourea potassium hydrogen
phthalate (TKHP) crystals by slow evaporation solution growth technique and its
physico-chemical properties have been discussed and which have not found in the
literature.
2. Experimental Procedure
2.1 Synthesis
TKHP salt was synthesized at room temperature by taking analytical grade
thiourea and potassium hydrogen phthalate in 1:1 stoichiometric ratio with Millipore
water as a solvent of 18.2 mΩ cm resistivity. The synthesized TKHP salt has been
obtained by the following chemical reaction and their reactants and product are
shown in Scheme 1. Stacking of TKHP crystal one over the other is shown in
Scheme 2.
[(NH2)2SC] + C8H5KO4 → [(C8 H4O3K)∙(NH)(NH2) SC
+.H2O]
(Thiourea + Potassium hydrogen phthalate → TKHP crystal)
290
Scheme 1. Molecular arrangement of TKHP crystal
2.2 Crystal Growth
The synthesized solutions were stirred vigorously at room temperature for 4h
using motorized magnetic stirrer. Continuous stirring with temperature 5°C greater
than room temperature ensures homogeneous mixing of solutions. Purification of the
synthesized salt was achieved by successive recrystalization process. The saturated
solution was filtered with watman filter paper of micron pore size and this
synthesized clear solution was poured into a petri dish and covered with pores paper
for slow evaporation of the solvent. After a span of two weeks the solvent was
evaporated and good quality TKHP crystals of size 5mm x 4mm x 3mm were
harvested from the Petri dishes. The grown crystal was defect less and optically
transparent with no inclusions. As-grown crystal TKHP is shown in figure 1. In this
acid-base interaction polarizable cation (K+) of noncentrosymmetrical system,
derived from potassium hydrogen phthalate linked to the thiourea through a
hydrogen bond network. In this complex TKHP, Sulphur atoms of thiourea
coordinated through Potassium atom of potassium hydrogen phthalate molecule and
the carbon atom in thiourea bonds with one sulphur and two nitrogen atoms.
Formation of water molecules facilitates, bond between one amino group hydrogen
to hydroxyl group of potassium hydrogen phthalate.
291
Figure 1 As-grown crystal of TKHP by slow evaporation technique
3. Characterizations of TKHP crystal
X- ray diffraction studies of the grown crystal were obtained on a PHILIPS
XPERT MPD system. The grown crystal of TKHP was subjected to absorption study
by using LAMBDA-35 UV-vis Spectrometer. Thermo gravimetric and differential
thermal analysis were carried out on NETZSCA STA 409 instrument heating rate of
20°C min-1 from 50°C to 500°C. The SHG efficiency of the grown crystal was
measured by KURTZ and PERRY powder technique using ND: YAG laser of
wavelength 1064nm.
4 Results and discussion
4.1 Single Crystal XRD Studies
The single crystal XRD study confirms the unit cell parameters of the TKHP
crystals a=6.439Å; b=9.565Å; c=13.241Å; α = β = γ = 90˚; and the volume of the
unit cell is found to be 815Å3.. Hence the result shows that TKHP species belong to
orthorhombic crystal system.. Same values of α, β and γ of TKHP indicates that there
is no change in orthorhombic crystal systems due to thiourea in potassium hydrogen
phthalate crystals (α=β=γ=90˚). Small change in the cell volume of TKHP (815Å3)
compared with KHP (861Å3).This analysis indicates that the addition of thiourea
ligand in the potassium hydrogen phthalate crystal does not change the crystal
structure though there is a small change in lattice parameters.
5 mm
4 m
m
292
10 20 30 40 50
0
100
200
300
400
500
600
700
800
900
(002
) (011
)
(012
)
(111
)(1
12)
(020
) (021
)(1
20)
(201
) (210
)(1
22)
(023
)
(123
)(0
15) (221
)
(132
)
(106
)(2
05)
(034
)(2
31) (232
)(3
20)
(141
)
KHA + Thiourea
Inte
nsity
(a.u
)
2 (degree)
200 300 400 500 600 700 800 900
0
1
2
3
4
5
Abs
orba
nce
(a.u
)
Wavenumber (nm)
4.2 Powder XRD studies
Powder x-ray diffraction study of TKHP crystal is shown in Fig 2. From the
XRD pattern, the observed sharp and well defined peaks without any broadening
confirm the grown sample is in good crystalline nature.
Figure 2 Powder XRD of grown
TKHP crystal
4.3 UV- Visible spectrum analysis
The selective electronic absorption spectrum of TKHP crystal recorded in the
range 200 -900 nm is shown figure 3. Optically polished single crystal of thickness 3
mm was used for this study. The recorded absorption spectrum, UV and Visible light
promote electrons in σ and π orbital from ground state to a higher energy state with a
limited introduction about the structure of the molecule. The absorption spectrum
shows the grown crystal has a lower cutoff wavelength at 290 nm, that attributes the
electronic transitions in the aromatic ring of TKHP crystals. Absence of absorbance
in the region between 290 nm to 900 nm is an essential property of the NLO
materials. The grown TKHP crystal has transparency close to 100% in the UV-
Visible and IR region and hence, the crystal can be used as a sensor material for UV,
Visible and in the IR regions.
This wide range of
transparency close to 100%
transmission shows that the
grown TKHP crystal is a
potential candidate for the
optoelectronic applications
[22].
Figure 3 UV-Visible-NIR absorption spectrum of as-grown TKHP crystal
293
4.4 Thermal studies
TGA and DTA curves of TKHP crystal are shown in figure 4. Crystal samples
were weighed in an Al2O3 crucible with temperature control facility. Thermo-
gravimetric (TG) /differential thermal (DT) analysis curves between ambient
temperatures to 500˚C of TKHP crystals recorded in nitrogen atmosphere were
shown in figure 5. The DTA curve of TKHP crystal shows two stage
decompositions. First stage decomposition was observed between 275°C to 340°C
with the exact decomposition temperature at 305.1°C.
Figure 4 TG&DTA curves of as-grown TKHP crystal
As a second stage, the decomposition temperature lies at 442.4°C in the range
430- 455°C. No weight loss between 50°C and 137.6°C indicates, that there is no
inclusion of solvent in the as grown TKHP crystal lattice, which was used for
crystallization. DTA endothermic peak shows melting point of as-grown TKHP
crystal at 305.1°C. The TG spectrum reveals that the gradual weight loss starts at
137.6°C [2.568mg-0.0%] and at 183.6°C it is about 2.538mg (Loss:1.2%);
continuous up to 245.7 °C [2.531mg-1.75%]. The Major weight loss occurs between
245.7°C and 321°C and 1.506 mg (39.8%) was obtained as a residue. This nature of
weight losses indicating the decomposition of the material and after 321°C no weight
loss was observed. This was compared with the decomposition point of potassium
hydrogen phthalate (KHP) crystal 298°C [16].
294
4.5 NLO studies
To confirm NLO property of the TKHP crystal, powdered form of the grown
crystals were subjected to KURTZ and PERRY techniques, which is the powerful
tool for initial screening of materials for second harmonic generation [17]. The beam
of fundamental wave length λω =1064 nm (incident beam wave power Pω) from Q-
switched Nd: YAG laser was made to fall normally on the powder form crystal
sample, which was packed between two optically transparent glass slides. Here
standard KDP has taken as a reference material. The SHG behavior of the TKHP
sample was confirmed by emission of bright green radiation wavelength λ=532nm of
power P2ω. The measured amplitude of second harmonic green light of TKHP crystal
was 10.8 mJ against 8.8 mJ for KDP crystal. The powder SHG efficiency of TKHP
crystal is about 1.2 times of KDP. Enhancement of SHG efficiency in TKHP crystal
is due to the stoichiometric addition of thiourea in potassium hydrogen phthalate,
facilitate molecular charge transfer and alignment of dipole moment in a parallel
manner. This enhanced SHG efficiency indicates, that the grown TKHP crystals can
effectively replace conventional nonlinear optical devices.
4. Conclusion
Good optical quality crystals of thiourea potassium hydrogen phthalate
(TKHP) were grown by the slow evaporation technique with the dimension size
5mm x4mm x3mm. Powder XRD study reveals, that the grown TKHP crystal is in
good crystalline nature. From single crystal XRD study orthorhombic systems of the
grown crystal are confirmed. UV–visible absorption spectral study shows wide
range of transmission bands (100%) with lower cutoff wavelength 290 nm..TGA and
DTA spectral analysis confirms the thermal stability of the grown crystals. Second
harmonic generation study of the grown TKHP crystal shows that, it is having NLO
property and their SHG efficiency is greater than standard KDP.
References
[1] Santhanu Bhattucharya, Parthasarathi, T.N. Guru Row, Chem. matter. 6 (1994)
531-537.
[2] Y.J.Ding, X.Mu, X.Cu, J. Nonlinear Opt. Phy. Matter. 9 (2000) 21.
295
[3] N.Karthick,R.Sankar,R.Jayavel,S.Pandi, J.Cryst .Growth, 312 (2009) 114-119.
[4] C.B. Aakeroy, P.B. Hitchcock, B.D. Moyle, K.R. Seddon, J. Chem. Soc., Chem.
Commun. (1992) 553-555.
[5] Ch.Bosshard, K.Sutter, Ph.Pretre, J.Hulliger, M.Florsheimer, P.Kaatz, P.Gunter,
organic Nonlinear optical materials, Gordon and Breach, Basel, 1995.
[6] M.C. Etter, J. Chem. Phy. 95 (1991) 4601-4610.
[7] L.M. Belyaev, G.S. Belikova, A.B. Gilvarg, I.M. Silvestrova, Sov. Phys.
Crystallogr.14 (1970) 544-.
[8] M.H.J. Hottenhuis, C.B. Lucasius, J. Crystal Growth 78 (1986) 379-388.
[9] M.H.J. Hottenhuis, C.B. Lucasius, J. Crystal. Growth, 91 (1988) 623-631.
[10] M.H.J. Hottenhuis, C.B. Lucasius, J. Crystal Growth 94 (1989) 708-720.
[11] S. Debrus, H. Ratajczak ,J. Venturini, N. Pincon ,J. Baran, J. Barycki,T.
Glowiak, A. pietraszko, Synthetic Metals 127 (2002) 99-104.
[12]Y.Lefur, M.Bagiue-Beucher, R.Masse, J.F.Nicoud, J.P.Levy, Chem.Mater. 8,
(1996) 68-71.
[13] H.Ratajczak, J.Baran, J.Barycki, S.Debrus, M.May, A.Pietraszko,
H.M.Ratajczak, A.Tramer, J.Venturini, J.Mol.Struct. 555 (2000) 149-158.
[14] H. Ratajczak, S. Debrus, M. May, J. Barycki, J. Baran, Bull. Pol. Acad. Sci.
Chem. 48 (2000) 189-192.
[15] P.R. Newman, L.F. Warren, P. Cunningham, T.Y.Chang, D.E. Copper, G.L.
Burdge, P. Polak dingles., C.K. Lowe-Ma, Advanced Organic Solid State
Materials, 173 (1990) 557-561.
[16]M. Oussaid, P. Becker, M.C. Kemiche, Carabatos-Nedlec, Phs. Stat. Sol. B 207
(1998) 103-110.
[17] S.K.Kurtz, J.J.Perry, J. Appl. Phys, 39 (1968) 3798-38136.
296
SOLUTION OF COUPLED NONLINEAR EQUATION BY
VARIATIONAL ITERATION METHOD
M.Sudhalakshmi1, R.Sivakumar2 1 Department of Physics, Shanmuga Industries Arts and Science College,
Tiruvannamalai District- 606601, Tamil Nadu 2 Department of Physics, Pondicherry University, Pondicherry - 605 014
ABSTRACT
It is shown in this paper one of the recently developing analytical techniques
viz., the Variational iteration method (VIM) to a special kind of nonlinear
differential equations. Variational iteration method (VIM) does not require any
linearization procedures to solve the
PDEs under consideration and also no computing facilities are needed. The results
show that this method gives reasonably accurate values compared with analytical
solution even with two iterations itself.
Key words: Analytical solution; Variational iteration method; Nonlinear equation
1. INTRODUCTION
Nonlinear partial differential equations (NLPDE) are widely used to describe
complex phenomena in various fields of science, especially in physics. Numerical
methods such as finite difference or characteristics method need a large amount of
computation and the effect of round-off error which causes the loss of accuracy. In
the last two decades with the rapid development of nonlinear science, there has
appeared ever increasing interest of scientists and engineers in the analytical
techniques. The investigation of exact solution of NLPDE’s plays an important role
in the study of nonlinear physical phenomena. Burger's equation [1, 22] is a useful
model equation which governs shock wave, acoustic transmission, traffic and
aerofoil flow theory, turbulence and supersonic flow as well as a prerequisite to the
Navier-Stokes equations. Burgers equation is a proper model for testing numerical
algorithm in flows. It is a useful model equation applied to complicated fluid flow
problems and interesting challenge for the control design. Analytical methods for
solving Burger's equation are very restricted and can be used in very special cases; so
they cannot be used to solve equations of numerous realistic scenarios. VIM is one
297
such analytical technique. He's variational iteration method is a powerful device for
solving functional equations.
2. HE'S VARIATIONAL ITERATION METHOD
He [7]-[17] has recently attracted a great deal of attention for solving easily and
efficiently a number of nonlinear functional equations. The main feature of the
proposed Variational Iteration Method [9, 25] is the solution of a mathematical
problem with linearization assumption is used as initial approximation (trial-
function), and then a more highly precise approximation at some special point can be
obtained. Variational iteration method (VIM) [14] is uniquely qualified to address
this challenge; the flexibility and adaptation provided have made the method a strong
candidate for approximate analytical solution and wide applications in various fields.
It provides physical insight into the nature of the solution of the problem and finds
accurate solution among all the possible trial-functions. He's method turns the
functional equation into a recurrence sequence of functions is the exact solution.
The keystone of the VIM is a generalized Lagrange multiplier determined by
stationary conditions imposed on an appropriate correction functional. The
convergence VIM is systematically discussed by Tatari and Dehghan.
z)y,x,g(t, Nu (u)L (u)L (u)L (u)L zyxt (1)
we constructs the correction functional as,
,0,0
~
1
ndssgsuNsLustutu
t
nnnn (2)
where general Lagrange multipliers can be identified via variational theory, the
nonlinear term and the analytical function usually taken as correction. He [8]-[17]
took the non linear term as restricted so as to find the approximate Lagrange
multiplier which helps in solving the equation to get the exact solution. The variation
operator on the restricted variation term leads to zero i.e 0~nu .. The subscript n
denotes the nth-order approximation.
3. COUPLED NONLINEAR EQUATIONS
3.1. ONE DIMENSIONAL TIME DEPENDENT COUPLED BURGER
EQUATION.
298
(3)
(4)
are subjected to the following initial conditions:
xxu sin)0,( (5)
xxv sin)0,( (6)
After constructing correction function and applying calculus of variation on both
sides we get
of 3 and 4 we have,
Where, 21 are general Lagrange multipliers and are ~
nxn uu ,~
nxn vv ,x
nn vu
~
restricted
variations i.e. 0~~~
xnnnxnnxn vuvvuu .
Applying He's calculus of variation we get,
dututtyxu n
t
tntn 0
'111 //)(1),,(
dvtvttyxv n
t
tntn 0
'221 //)(1),,(
Stationary conditions thus obtained as,
(7)
299
(8)
Lagrange multipliers 21, are
(9)
(10)
Substituting Lagrange multipliers and 0n the iteration equations is as follows,
(11)
(12)
start with the arbitrary initial approximation that satisfies the initial conditions
xxu sin)0,( (13)
xxv sin)0,( (14)
Using 13 and 14 in 11 and 12 gives,
xtxtxu sinsin),(1 (15)
xtxtxv sinsin),(1 (16)
Substituting Lagrange multipliers and 3,2,1 nnn the second, third and fourth
iteration equations are as
xtxtxtxu sin2
sinsin),(2
2 (17)
xtxtxtxv sin2
sinsin),(2
2 (18)
xtxtxtxtxu sin3*2
sin2
sinsin),(32
3 (19)
xtxtxtxtxv sin3*2
sin2
sinsin),(32
3 (20)
xtxtxtxtxtxu sin!4
sin!3
sin!2
sinsin),(232
4 (21)
300
xtxtxtxtxtxv sin!4
sin!3
sin!2
sinsin),(232
4 (22)
Extending this iteration, we can show that
...sin!4
sin!3
sin!2
sinsin),(232
xtxtxtxtxtxu
=
...
!4!3!21sin
232 ttttx
= xt sin)exp( (23)
...sin!4
sin!3
sin!2
sinsin),(232
xtxtxtxtxtxv
=
...
!4!3!21sin
232 ttttx
= xt sin)exp( (24)
We now calculate the numerical results of the solution of one dimension coupled
time dependent Burger equation 3 and 4 using equations 21 and 22. These values are
compared with 23 and 24. The error in the solutions obtained by Variational Iteration
Method is the absolute difference between analytical values and equations 3 and 4.
They are tabulated in table 1, from the table we
observed that the absolute error is smaller for least t values. x for different values
of t for ),(4 txu is shown in figure 1. Proceeding with higher iterations we can
increase the accuracy of the numerical solution.
Table 1: Numerical results for ),(4 txu or ),(4 txv of one dimension time dependent coupled
Burger equation in comparison with the analytical solution
t x Exact solution VIM solution Absolute error
0.1 0.090333010952424 0.090333019135174 -0.0818e-007
0.2 00.179763444319535 0.179763460603276 -0.1628e-007
0.3 0.267397740772900 0.267397764994930 -0.2422e-007
0.4 0.352360287390403 0.352360319308704 -0.3192e-007
0.1
0.5 0.433802166491126 0.433802205786781 -0.3930e-007
301
0.6 0.510909637740202 0.510909684020580 -0.4628 e-007
0.1 0.081736688393606 0.081736945989313 -0.0818e-007
0.2 0.162656690815339 0.162657203432943 -0.1628e-007
0.3 0.241951481349599 0.241952243867194 -0.2422e-007
0.4 0.318828772660741 0.318829777459502 -0.3192e-007
0.5 0.392520432266236 0.392521669306548 -0.3930e-007
0.2
0.6 0.462290157462532 0.462291614384295 -0.4628 e-007
0.1 0.073958414084880 0.073960338805095 -0.0192e-004
0.2 0.147177860143625 0.147181690352886 -0.0383e-004
0.3 0.218926753674347 0.218932451102470 -0.0570e-004
0.4 0.288488203449919 0.288495711170085 -0.0751e-004
0.5 0.355167174458140 0.355176417455691 -0.0924e-004
0.3
0.6 0.418297432461834 0.418308318383795 -0.1089e-004
0.1 0.066920340442597 0.066928322520034 -0.0798e-004
0.2 0.133172034964415 0.133187919365009 -0.1588e-004
0.3 0.198093118533691 0.198116746545762 -0.2363e-004
0.4 0.261034921143457 0.261066056683719 -0.3114e-004
0.5 0.321368549107831 0.321406881080258 -0.3833e-004
0.4
0.6 0.378491168759837 0.378536314164032 -0.4515e-004
Figure 1: Solution of obtained ),(4 txu by VIM versus x for different values of
time
302
3.2 TWO DIMENSIONAL BURGER EQUATION
(25)
(26)
where Re is the Reynolds number and subjected to the following initial conditions:
(27)
(28)
and
After constructing the correction function we get the Lagrange multipliers as
Applying He's calculus of variation, the iteration equations are as
dvuuvuuutyxutyxut
nyynxxnynnxnnnn
0
~~
1 )(Re1),,(,,
(29)
dvvvvvuvtyxvtyxvt
nyynxxnynnxnnnn
0
~~
1 )(Re1),,(,,
(30)
We start with the arbitrary initial approximation that satisfies the initial conditions
and substituting 0n in 29 and 30 the first iteration equations are,
303
te
ee
tyxu 211128
Re)1(4
143),,(
(31)
te
ee
tyxv 211128
Re)1(4
143),,(
(32)
To get the second iteration we put 1n 1 in 29 and 30
We now calculate the numerical results of the solution of two dimensional coupled
homogeneous Burger equation 25 and 26 using equations 33 and 34.These values are
compared with analytical solutions given by
304
The error in solutions obtained by Variational Iteration Method is the absolute
difference between analytical values and 33 and 34. They are tabulated in Tables 2,
3. From these tables we observe that the absolute error is smaller than 610 even for
second iteration. To improve or reduce the error, we have to proceed with higher
iterations which becomes more complicated.
Table 1: Numerical results for ),,(2 tyxu 25 obtained by VIM method for Re = 100
at y = 1 in comparison with analytical solution
t x Exact solution VIM solution Absolute
error
0.1 0.749995555362034
0.749994383449127 -1.1719e-
006
0.2 0.749984487375994
0.749980397293144 -4.0901e-
006
0.3
0.749945863987526 0.749931591790085
-1.4272e-
005
0.4 0.749811148591818
0.749761377483330 -4.9771e-
005
0.5
0.749342081506279 0.749168894884322
-1.7319e-
004
0.1
0.6 0.747718590652705
0.747120525817792 -5.9806e-
004
0.1 0.749993924939814
0.749991314568159 -2.6104e-
006
0.2 0.749978797239569
0.749969686748774 -9.1105e-
006
0.3 0.749926010721622
0.749894219312531 -3.1791e-
005
0.4
0.749741942240811 0.749631068604713
-1.1087e-
004
0.2
0.5 0.749101599354645
0.748715700340454 -3.8590e-
004
305
0.6 0.746892087286704
0.745558428188497 -1.3336e-
003
0.1 0.749991696451263
0.749987560789737 -4.1357e-
006
0.2
0.749971020164203
0.749956585568673
-1.4435e-
005
0.3 0.749898879625539
0.749848501385006 -5.0378e-
005
0.4 0.749647410375845
0.749471615822517 -1.7579e-
004
0.5 0.748773648573570
0.748160618831361 -6.1303e-
004
0.3
0.6 0.745771271683318
0.743639619092962 -2.1316e-
003
0.1 0.749988650532824
0.749983329906607 -5.3206e-
006
0.2 0.749960390945224
&0.749941817339808 -1.8574e-
005
0.3 0.749861805340769
0.749796943162410 -6.4862e-
005
0.4 0.749518316334168
0.749291517140896 -2.2680e-
004
0.5 0.748326787268929
0.747530433123219 -7.9635e-
004
0.4
0.6 00.744255657522494
0.741427052666243 -2.8286 e-
003
0.1 0.749984487375994
0.749979183188871 -5.3042e-
006
0.2 0.749945863987526
0.749927335866920 -1.8528e-
005
0.5
0.3 0.749811148591818
0.749746300778153 -6.4848e-
306
005
0.4
0.749342081506279 0.749113594321782
-2.2849e-
004
0.5
0.747718590652705 0.746896033502150
-8.2256e-
004
0.6 0.742214042366305
0.739079589133349 -3.1344e-
003
0.1 0.749978797239569
0.749976306431121 -2.4908e-
006
0.2 0.749926010721622
0.749917265736494 -8.7450e-
006
0.3 0.749741942240811
0.749710798008835 -3.1144e-
005
0.4 0.749101599354645
0.748985437415671 -1.1616e-
004
0.5 0.746892087286704
0.746400296384409 -4.9179e-
004
0.6
0.6
0.739478068021095 0.736877431048402
-2.6006e-
003
Table 1: Numerical results for ),,(2 tyxv 26 obtained by VIM method for Re = 100
at y = 1 in comparison with analytical solution
t x Exact solution VIM solution Absolute error
0.1 0.750004444637966 0.750005616550873 1.1719 e-006
0.2 0.750015512624006 0.750019602706856 4.0901e-006
0.3 0.750054136012474 0.750068408209915 1.4272 e-005
0.4 0.750188851408182 0.750238622516670 4.9771 e-005
0.5 0.750657918493721 0.750831105115678 1.7319 e-004
0.1
0.6 0.752281409347295 0.752879474182208 5.980 e-004
0.1 0.750006075060186 0.750008685431841 2.6104e-006 0.2
0.2 0.750021202760431 0.750030313251226 9.1105e-006
307
0.3 0.750073989278378 0.750105780687469 3.1791e-005
0.4 0.750258057759189 0.750368931395287 1.1087e-004
0.5 0.750898400645355 0.751284299659546 3.8590e-004
0.6 0.753107912713296 0.754441571811503 1.3336e-003
0.1 0.750008303548737 0.750012439210263 4.1357e-006
0.2 0.750028979835797 0.750043414431327 1.4435e-005
0.3 0.750101120374461 0.750151498614994 5.0378e-005
0.4 0.750352589624155 0.750528384177483 6.1303e-004
0.5 0.751226351426430 0.751839381168639 1.7579e-004
0.3
0.6 0.754228728316682 0.756360380907038 2.1316e-003
0.1 0.750011349467176 0.750016670093393 5.3206e-006
0.2 0.750039609054776 0.750058182660192 1.8574e-005
0.3 0.750138194659231 0.750203056837590 6.4862e-005
0.4 0.750481683665832 0.750708482859104 2.2680e-004
0.5 0.751673212731071 0.752469566876781 .9635e-004
0.4
0.6 0.755744342477506 0.758572947333757 2.8286e-003
0.1 0.750015512624006 0.750020816811129 5.3042e-006
0.2 &0.750054136012474 0.750072664133080 1.8528e-005
0.3 0.750188851408182 0.750253699221847 6.4848e-005
0.4 0.750657918493721 0.750886405678218 2.2849e-004
0.5 0.752281409347295 0.753103966497850 8.2256e-004
0.5
0.6 0.757785957633695 0.760920410866651 3.1345e-003
0.1 0.750021202760431 0.750023693568879 2.4908e-006
0.2 00.750073989278378 0.750082734263506 8.7450e-006
0.3 0.750258057759189 0.750289201991165 3.1144e-005
0.4 0.750898400645355 0.751014562584329 1.1616e-004
0.5 0.753107912713296 0.753599703615591 4.9179e-004
0.6
0.6 0.760521931978905 0.763122568951598 2.6006e-003
308
4. CONCLUSION
In this work, we have reviewed available literature, of numerical and analytical
methods on solving PDE's. We have selected one of the available analytical method
called Variational Iteration Method. We have applied VIM to solve various forms of
Burger equation. From the solutions we find that even with a very few iterations one
can get reasonably accurate solutions as we seen in the Tables 1, 2, 3. This indicates
that VIM is a powerful technique to find analytical solutions of PDE's. Extending
VIM method to coupled and nonlinear PDE's is still difficult since we have to start it
with an initial solution which is not known a priori.
5. BIBLIOGRAPHY
[1] R. Noorzad, A.T. Poor, M. Omidvar, Variational iteration method and homotopy-
perturbation method for solving Burgers equation in fluid dynamics. J. Applied Sci. 8
(2008) 373393 .
[2] H. Bateman, Some recent researches on the motion of fluids. Monthly Weather
Rev. 43 (1915) 170163 .
[3] J.D. Cole, On a quasi-linear parabolic equation occurring in aerodynamics. Qurat.
Appl. Math. Model 9 (1951) .236225
[4] D. Mitra, Studies of Static and Dynamic Multiscaling in Turbulence. Physica A
318 (2003) 186179 .
[5] X. Wu, J. Zhang, Artificial boundary method for two-dimensional Burger's
equation. Computer and Mathematics with Application 56 (2008) 256242 .
[6] J.H. He, A new approach to nonlinear partial differential equations. Commun.
Nonlinear Sci. Numer. Simul. 2 (1997) 235230 .
[7] J.H. He, Variational iteration method for delay differential equations. Commun.
Nonlinear Sci. Numer. Simul 2 (1997) 236235 .
[8] J.H. He, Approxmiate analytical solution for seepage flow with fractional
derivatives in porous media. Comput. Methods Appl. Mech. Eng 167 (1998) 6857 .
309
[9] J.H. He, A coupling method of a homotopy technique and a perturbation
technique for non-linear problems. Int. J. Non-linear Mech. 35 (2000) 4337 .
[10] J.H. He, A new perturbation technique which is also valid for large parameters.
J. Sound Vibration 229 (2000).
[11] J.H. He, Variational iteration method is a kind of nonlinear analytical technique:
some examples. Int. J. Non-linear Mech,. 34 (1999) 708699 .
[12] J.H. He, Some asymptotics methods for strongly nonlinear equations. Int. J.
Modern Phys. 20 (2006) 1141--1199.
[13] J.H. He, Variational iteration method - Some resent results and new
interpretations. J. Comput. Appl. Math. 207 (2007) 173 .
[14] J.H. He, X.H. Wu, Variational iteration method: New development and
applications. Computers and Mathematics with Application 54 (2007) 894881 .
[15] J.H. He,G.w. Wu,F. Austin, The VIM which should be followed. Non-linear
Science LettersA- Mathematics, physics & mechanics. 35 (2010).
[16] Sh.Q. Wang, J.H. He, Variational iteration method for solving integro-
differential equations. Phys. Lett. A 367 (2007) 191188 .
[17] J.H. He, Variational approach for nonlinear oscillators. Chaos, Solitons and
Fractals 34 (2007) 14391430 .
[18] S.J. Liao, An approximate solution technique not depending on small
parameters; a special example. Int. J. Non-Linear Mech. 30 (1995) 380371 .
[19] M. Mamode, Variational iteration method and initial-value problems Appl.
Math. Comput. 215 (2009) 282276 .
[20] W.X. Qian, Y.H. Ye, J. Chen, L.F. Mo, He's iteration formulation for solving
non-linear Algebraic equations. J. Phys. 96 (2008).
[21] S. Pamuk, A Review of some recent results for the approximate analytical
solutions of nonlinear differential equations. Hindawi publishing corporation (2009).
310
[22] G. Adomian, Solving Frontier Problems of Physics: The Decomposition
Method. kluwer (1994).
[23] D. Altintan, O. Ugur, Variational iteration method for Sturm-Liouville
differential equations. Computers and Mathematics with Applications. 58
(2009) 328322 .
[25] S.A.E. Wakil, M.A. Abdou, New applications of variational iteration method
using Adomian polynomials. Non-Linear Dynamics 52 (2008) 4941 .
[26] A.M. Wazwaz, The variational iteration method: A reliable analytic tool for
solving linear and nonlinear wave equations. Computers and Mathematics with
Applications 54 (2007) 932926 .
[27] J.A. Atwell, J.T. Borggaard, B.B. KING, Reduced Order Controllers for
Burgers Equation with a Nonlinear Observer. Int. J. Appl. Math. Comput. Sci. 11
(2001) 13301311 .
[28] S.M. Goh , M.S.M. Noorani , I. Hashim, A new application of variational
iteration method for the chaotic Rossler system. Chaos, Solitons and Fractals 42
(2009) 16101604 .
[29] A.M. Kawala, Numerical solution for Ito coupled systems. Acta Appl. Math.106
(2009) 335325 .
[31] A. Ghorbani , J.S. Nadjafi, An effective modification of He's variational
iteration method. Nonlinear Analysis: Real World Applications. 10 (2009)
28332828 .
[32] B.D.Hahn, Essential Matlab for Scientists. Elsevier 2002.
[33] J. Zhang, G. Yan, Lattice Boltzmann method for one and two-dimensional
Burgers equation. Physica A 387 (2008), 47864771 .
311
ULTRASONIC STUDIES ON THE EFFECT OF DIOXANE AND
TETRAHYDROFURAN ON THE MICELLIZATION
OF CETYL TRIMETHYL AMMONIUM BROMIDE
IN AQUEOUS SOLUTIONS
G. Lakshiminarayanan1 and D.Sakthivel2
1,2 Department of Physics, Shanmuga Industries Arts and Science College,Thiruvannamalai.
ABSTRACT
Ultrasonic velocity, density and viscosity studies have been carried out in
aqueous solutions of cetyl trimethyl ammonium bromide (CTAB) and in aqueous
solutions of CTAB containing 5-20% V/V of dioxane (DN), tetrahytrofuran (THF).
These studies are carried out in CTAB concentration of 0.5mM to 5mM at a fixed
frequency of 2MHz and at a fixed temperature of 303.15K. The variation of
ultrasonic velocity in aqueous solutions of CTAB containing 5-20% V/V of DN
and THF with CTAB concentration exhibiting a break at critical micelle
concentration (CMC). The ultrasonic velocity, adiabatic compressibility, free length,
free volume and internal pressure also exhibiting a break at CMC similar to velocity
curve. The results are discussed in terms of formation of CTAB micelles through
hydrophobic interaction and hydrogen bonding.
INTRODUCTION
Molecular interaction in liquid mixtures has been the subject of
numerous investigation in recent past years [1-6].The systems shows a wide verity of
physical properties. Resent researchers have studied the interaction of cetyl trimethyl
ammonium bromide (CTAB) with alcohol through ultrasonic techniques [7]. But the
effect of aprotic solvent on CTAB is scandy. The aim our present investigation is to
determine ultrasonic studies on the effect of dioxane and tetrahydrofuran on
the micellization of cetyl trimethyl ammonium bromide in aqueous solutions at
fixed frequency of 2 MHz and fixed temperature of 303.15 k. The results are
interpreted in terms of formation of CTAB micelles in the solutions.
MATERIALS AND METHODS
The cetyl trimethyl ammonium bromide (CTAB) used in the present study are
of AR/BDH grade purchased from SD-fine chemicals Ltd., India and they are used
312
as such without further purification. The solvents used namely Dioxane and
tetrahydrofuran are of spectroscopic grade. Triply distilled deionised water is used
for preparing the solutions of CTAB. Ultrasonic velocity studies are carried out at a
fixed frequency of 2 MHz in the cetyl trimethyl ammonium bromide concentration
range of 0.5mM to 5mM. Ultrasonic velocity is measured using a Digital Ultrasonic
Velocity meter (Model VCT-70A, Vi-Microsystems Pvt. Ltd., Chennai, India) at a
fixed temperature at 303.15K by circulating water from a thermostatically controlled
water bath and the temperature being maintained to an accuracy of ±0.1oC. The
accuracy in measurement of velocity and absorption is ±2 parts in 105 and 3%
respectively. Shear viscosity and density of aqueous solutions of CTAB containing
5-20% V/V of DN and THF are determined using an Oswald’s viscometer and a
graduated dilatometer respectively. The accuracy in measurement of density and
viscosity is ±2 parts in 104 and ± 0.1% respectively. From the measured values of
ultrasonic velocity, density and viscosity, the various other parameters such as
adiabatic compressibility (βs), intermolecular free length (Lf), free volume (Vf ) and
internal pressure (Пi) are calculated using standard formulae.
COMPUTATIONS OF PARAMETERS
Adiabatic compressibility (βs), intermolecular free length (Lf), free volume
(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),
respectively.
βs = 1/C2ρ (1)
Lf = KT βs 1/2 (2)
Vf = (M C / K η)3/2 (3)
πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)
where, c is ultrasonic velocity, ρ is density, KT is temperature dependant constant, M
is effective molecular weight, K is constant for liquids, b is constant, T is
temperature.
RESULT AND DISCUSSIONS
From the measured values of density, ultrasonic velocity and viscosity,
the other parameters such as adiabatic compressibility, free length, free volume and
313
internal pressure were computed and shown in graphically in figures (1-12).The
variations of ultrasonic velocity against concentration of Cetyl Trimethyl
Ammonium in aqueous solution are given in Figs. 1 & 2. The measured ultrasonic
velocity increases with increasing concentration of Cetyl Trimethyl Ammonium
bromide in aqueous solutions and exhibits sharp break at a particular concentration is
known as Critical Micellar Concentration (CMC), which is confirmed by Ionescu et
al [8]. The increase in ultrasonic velocity before CMC is due to the bromide ions
making hydrogen bond with water molecules. The micelle formation in aqueous
solution of Cetyl Trimethyl Ammonium bromide and higher aggregation leads to
increase in velocity after CMC.
The measured ultrasonic velocity increases with increasing
concentration of Cetyl Trimethyl Ammonium bromide in aqueous – aprotic solvent
(5-20%V/V of Dioxane and Tetrahydrofuran) mixtures of solution and exhibits sharp
break at a particular concentration of Cetyl Trimethyl Ammonium bromide (i.e.).,
CMC as shown in Fig 1 & 2. The increase in ultrasonic velocity is due to the aprotic
solvents act as a structure breaker in aqueous Cetyl Trimethyl Ammonium bromide.
Cetyl Trimethyl Ammonium ions are restricting the mobility of the water molecules.
This leads to increase in ultrasonic velocity for before CMC.The micelle
formation in aqueous-aprotic solution of Cetyl Trimethyl Ammonium bromide and
higher aggregation leads to increase in velocity for after CMC of solution. In
addition to dipole moment of dioxane in the solution also contributes increase in
ultrasonic velocity. The velocity observed in aqueous-aprotic solvent at particular
compositions (volume by volume) in the order:
Velocity of THF mixture > Velocity of Dioxane mixture.
From the figures 1 & 2, it is observed that when the 5% V/V of Dioxane is
added to the aqueous solution of Cetyl Trimethyl Ammonium Bromide, the CMC of
aqueous solution of Cetyl Trimethyl Ammonium bromide shifted towards the higher
concentration side (3 mM). This is due to the lowering of the average dielectric
constant of the medium because of the dielectric constant of water is greater than
dioxane.
Similarly, when the 10-20% V/V of dioxane is added to the aqueous solution
of Cetyl Trimethyl Ammonium Bromide, the CMC of aqueous solution of Cetyl
314
Trimethyl Ammonium Bromide shifted towards the higher concentration side in the
order of (3.5 mM), (4.0 mM), (4.5 mM), respectively.
All the above explanation is offered for the additive of Tetrahydrofuran of
various compositions except the breaking value of CMC. Here, the observed value
of CMC is 2.5 mM, 3.0 mM, 3.5 mM and 4.0 mM by addition of 5% of THF, 10%
of THF, 15% of THF and 20% of THF, respectively. This is due to the difference in
dielectric constant of the dioxane and tetrahydrofuran in these solutions.
Adiabatic compressibility, free length and free volume, internal pressure
studies supports the ultrasonic velocity studies in aqueous and aqueous aprotic
solvents mixtures.
CONCLUSION
In the present study, the ultrasonic velocity, density, viscosity and internal
pressure increases whereas adiabatic compressibility, free length and free volume
decreases with increasing concentration of Cetyl Trimethyl Ammonium Bromide in
aqueous and aqueous – aprotic solvent (Dioxane and Tetrahydrofuran) mixtures.
Ultrasonic velocity of THF is slightly higher than dioxane for all aqueous and
aqueous – aprotic solvent (Dioxane and Tetrahydrofuran) mixtures because of due to
their difference in dipole moment.
The CMC values are obtained in aqueous and aqueous – aprotic solvent
(Dioxane and Tetrahydrofuran) mixtures of various compositions of concentration of
Cetyl Trimethyl Ammonium Bromide solutions. The higher CMC values in aqueous
– dioxane mixtures for various composition compared to aqueous – tetrahydrofuran
mixtures of various composition of concentration of Cetyl Trimethyl Ammonium
Bromide. This is due to the average dielectric constant modification in aqueous –
aprotic solvent (Dioxane and Tetrahydrofuran) mixtures of Cetyl Trimethyl
Ammonium Bromide.
315
0.000 0.001 0.002 0.003 0.004 0.005
1495
1500
1505
1510
1515
1520
1525
1530
1535
1540(c
)m s
-2
(X) mol dm-3
Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB
0.000 0.001 0.002 0.003 0.004 0.005
1495
1500
1505
1510
1515
1520
1525
1530
1535
1540
1545
1550
(c)m
s-2
(X) mol dm-3
Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB
0.000 0.001 0.002 0.003 0.004 0.0054.124.144.164.184.204.224.244.264.284.304.324.344.364.384.404.424.444.464.484.50
() x
10-1
0 m2 N
-1
(X) mol dm-3
Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB
0.000 0.001 0.002 0.003 0.004 0.005
0.406
0.408
0.410
0.412
0.414
0.416
0.418
0.420
0.422
0.424
(Lf)
x 10
-10 m
(X) mol dm-3
Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB
0.000 0.001 0.002 0.003 0.004 0.005
0.400
0.405
0.410
0.415
0.420
0.425
(Lf)
x 10
-10 m
(X) mol dm-3
Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB
0.000 0.001 0.002 0.003 0.004 0.005
4.00
4.05
4.10
4.15
4.20
4.25
4.30
4.35
4.40
4.45
4.50
() x
10-1
0 m2 N
-1
(X) mol dm-3
Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB
316
References
1) P.G.T. Fogg, J. Chem. Soc., 83, 117 (1958).
2) J. Millar and A.J. Parker J. Am. Chem. Soc., 83, 117 (1961).
3) D.S. Allam and W. N. Lee, J. Chem. Soc., 6049 (1964).
4) S. Nakamura and S. Meiboom, J. Chem. Soc., 89, 1765 (1967).
5) K. Ramabrahaman, Ind.J.Pure.Appl.Phys.6,75 (1968)
6) C.V. Chaturvedi and S. Prakash, Ind. J.Chem.,10,669(1972)
7) Girish Kumar, Mohinder S Chauhan, Akshat Kumar, Suvercha Chauhan
and Rajesh
Kumar Der Chemica Sinica, 3, 628-635 (2012).
8) Lavinel G.Ionescu, Tadashi Tokuhiro, Benjamin J. Czerniawski, Eric S.
Smith,
Solution Chemistry of Surfactants, 487-496 (1979).
0.000 0.001 0.002 0.003 0.004 0.0051.051.101.151.201.251.301.351.401.451.501.551.601.651.701.751.801.851.901.952.00
(Vf) x
10-6
m
(X) mol dm-3
Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB
0.000 0.001 0.002 0.003 0.004 0.0051.151.201.251.301.351.401.451.501.551.601.651.701.751.801.851.901.952.00
(Vf)
x 10
-6 m
(X) mol dm-3
Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB
0.000 0.001 0.002 0.003 0.004 0.0050.660.680.700.720.740.760.780.800.820.840.860.880.900.920.940.960.981.001.021.041.06
()
x 10
3 pas
cal
(X) mol dm-3
Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB
0.000 0.001 0.002 0.003 0.004 0.0050.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
()
x 10
3 pas
cal
(X) mol dm-3
Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB
317
SYNTHESIS, GROWTH AND CHARACTERIZATION OF
Cd2+ DOPED ZTS CRYSTALS
J.Rajeswari
Department of Physics, Shanmuga Industries Arts and Science College , Tiruvannamalai
ABSTRACT
This article deals with Growth and characterization of doped ZTS crystals, we
have grown cadmium ion doped ZTS crystals by slow evaporation solution growth
technique. To know its suitability for device fabrication, different characterization
analyses have been performed. By powder X-ray diffraction (PXRD) method the it is
found that it exhibits crystalline nature. The thermal stability of the crystal was
examined by TG/DTA analysis and it is observed that the crystal is thermally stable
up to 232° C. Its relative second harmonic generation efficiency was evaluated from
Kurtz powder technique.The mechanical property of the crystal was tested by
Vicker’s microhardness tester.
Key words : Crystal growth , FTIR , TG/DTA, SHG, Micro hardness
1. Introduction:
Nonlinear optics (NLO) is a field of science and technology, which finds wide
applications in the field of telecommunication, optical information and optical
storage devices etc. [1-3]. Recent advances in organic Nonlinear Optical (NLO)
materials have involved a large revival of interest on account of their widespread
potential importance such as their high nonlinearity, high flexibility in terms of
molecular structure, high optical damage threshold [4, 5]. The origin of nonlinearity
in NLO material like thiourea arises due to the presence of delocalized Π electrons
system, connecting donor and acceptor groups and responsible for enhancing their
asymmetric polarizability [6].
Zn(CS(NH2)2)3SO4 is a good engineering material for device applications and
one of the semiorganic nonlinear optical materials (NLO) for second harmonic
generation (SHG) [7,8].ZTS is an important metal-organic crystal. It is used for
electro-optical applications and frequency doubling of near IR laser radiations [9].
In this present study, we examined the effect of doping of cadmium ion with
ZTS on its optical, mechanical and thermal properties.
318
2. Experimental:
Thiourea and zinc sulphate heptahydrate (AR grade) were taken in the ratio
1:3 and dissolved in Millipore water of 18.1 MΩ-cm. The solution was thoroughly
mixed using a magnetic stirrer. It was left for slow evaporation .A crystalline
substance was formed. This synthesized substance was purified by repeated
crystallization process.
A saturated solution was prepared using the recrystallized salt and Millipore
water at room temperature with continuous stirring. The solution was then filtered
using Wattmann filter paper. The filtered solution was poured in to petri dishes and
covered with perforated sheet. It was left undisturbed for slow evaporation. Good
quality ZTS crystals were obtained within 20 days. It is shown in Fig.1.
To grow Cd2+ doped ZTS crystals , 1.1M of cadmium sulphate was added to
the saturated solution of ZTS and stirred continuously to obtain the the homogenous
solution. The solution was then filtered and left for slow evaporation. Crystals with
average size of 8 x 4 x 3 mm3 were obtained after 22 days. As grown Cd2+ doped
ZTS crystals were shown in Fig.2.
Figure.1 Pure ZTS Crystals Figure.2 Cd2+ doped ZTS crystals
3. Characterization techniques:
Fourier transform infrared (FT-IR) spectra were recorded for cadmium doped
ZTS specimens using Perkin Elmer Spectrum RXI spectrophotometer by KBr pellet
technique. Powder X-ray diffraction analysis was also carried out for the grown
crystals in order to understand the crystalline nature of the material using an X-ray
diffractometer. Finely the grounded powder samples were subjected to powder X-ray
319
diffraction analysis using Brucker D8 advance model instrument. The sample was
scanned over the range 10-60° at the rate of 0.02° /minute. To study the thermal
stability of the compound the simultaneous thermo gravimetric analysis (TGA) and
differential thermal analysis (DTA) curves for grown crystals were obtained using a
Seiko TG/DTA 6200 model analyzer in nitrogen atmosphere. The second harmonic
generation test was performed by the Kurtz and Perry powder technique. Adopting
Vicker’s microhardness tester , the mechanical stability of the crystal was tested.
4. Result and Discussion:
4.1 FTIR studies:
The FTIR spectrum of doped crystals is shown in Fig.3. These spectra show a
broad envelope lying in between 2845 cm-1 and 3990 cm-1 and this corresponds to
the symmetric and asymmetric stretching modes of NH2 grouping zinc coordinated
thiourea. The NH2 bending vibration is observed at 1623 cm-1 (10). The C=S
asymmetric stretching vibration is observed the band 715 cm-1. The absorption at
1505 cm-1 is arising out of N-C-N stretching vibration. The band at 461 cm-1 is due
to asymmetric N-C-N bonding. The presence of sulphate ion is confirmed by the
absorption band at 620 cm-1 and 1109 cm-1(10). The presence of additional peak 992
cm-1 in the lower frequency region may be due to the presence of Cadmium in the
coordination sphere.
4.2 Powder XRD studies:
The X-ray diffraction pattern of doped ZTS crystal was shown in Fig.4.The
sharp peaks in the XRD patterns confirm the crystalline nature of the grown
materials. The shift in the peaks of XRD pattern of doped ZTS indicates the
incorporation of cadmium ion in ZTS crystals [11].
4.3 NLO study:
The fundamental Q switched Nd: YAG laser beam of wavelength 1064 nm
with 8 ns pulse width and repetition rate of 10 Hz was used as source. The sample
crystals were powdered and tightly packed between glass slides. The beam was
directed on the powdered sample. The input laser energy incident on the capillary
tube was chosen as 6 J. The second harmonic generation was confirmed by the
emission of green radiation. The second harmonic signal of 202 mV was obtained
320
for Cd2+ doped ZTS crystals, which is 190 mV for pure ZTS. There is slight increase
in the efficiency of ZTS crystals due to doping
4.4 Microhardness studies :
The micro hardness is measured as the ratio of applied load to the surface area
of the indentation. The indentations were carried out using Vicker's indenter for
varying loads. For each load, two indentations were made and the average value of
the diagonal length (d) was used to calculate the micro hardness.
A plot drawn between the hardness value and corresponding loads for
cadmium doped ZTS crystal is shown in Fig. 5. The hardness number was found to
increase with the load. The increase in hardness number of the doped crystal is due
to the strong bond formed between the sulphur and cadmium ions (12).
4.5 Thermal studies. :
The thermogram and differential thermogram of Cd2+ doped ZTS are shown
in Figure 6. From the TGA curve it is inferred that the sample does not have any
water molecules as there is no weight loss around 100° C [13]. The sharp
endothermic peak at 232.1° C is assigned to the melting point of the crystal. The
sharpness of this peak shows the high degree of crystalline nature and purity of the
sample. The crystal has thermal stability of 232.1° C. The second endothermic peak
at 357.5 ° C corresponds to the decomposition of cadmium which also shows the
evidence for the inclusion of cadmium. Above this temperature, zinc starts to melt
and then at 816.9 ° C all the
residues melt.
Fig.3. FTIR spectrum of Cd ions doped ZTS crystal
321
Fig.4. Powder XRD pattern of Cd2+ doped ZTS crystals
Fig.5..LogPVsHv for grown crystal Fig.6. TG/DTA of the sample
5. Conclusion:
The single crystals of ZTS and cadmium doped ZTS were grown by slow
evaporation technique. The crystalline nature of the samples was confirmed powder
X-ray diffraction analysis. FTIR studies identify the functional groups present in the
compound. The SHG analysis reveals that the doping of cadmium increases the
efficiency of ZTS crystal. The hardness study shows the increasing nature of
hardness number with the increase in load. From the thermal studies, it is inferred
20 30 40 50 60 70 80 90 100 11060
70
80
90
100
110
120
Microhardness of Cd2+ doped ZTS
Hv
Load in g
Temp Cel900.0800.0700.0600.0500.0400.0300.0200.0100.0
TG %
104.0
102.0
100.0
98.0
96.0
94.0
92.0
90.0D
TA u
V
15.00
10.00
5.00
0.00
-5.00
-10.00
-15.00
-20.00
3.2%
1.0%
232.1Cel-17.55uV
816.8Cel3.27uV
322
that the doped crystals were thermally stable up to 232.1° C and the doping does not
alter the thermal property of pure ZTS crystals.
References:
1. G. Penn Benjamin, H. Beatriz, Cardelino,Moore Craig E., W. Shields Angels,
D.O.Frazier, (1991). Prog. Cryst. Growth Charact. 22:19.
2. V. Venkataramanan, G. Dhanaraj, H.L. Bhat.,(1994). J. Crystal Growth 140:336.
3. C. Krishnan, P. Selvarajan, T.H. Freeda.,(2008). J. Crystal Growth 311:141.
4. V. Bisder-Leib, M.F. Doherty., (2003). Cryst.Growth Des. 3:221.
5. I. Lediux, J.Badan, J. Zyss. A migus D.Hulin,J.Etchepare, G. Grillon and A.
Antonetti.,(1987) . J.Opt.Soc.Am. B4 (6):987.
6. P.Selvarajan, J.Glorium Arul Raj, S. Perumal.,(2009). J. Crystal Growth
311:3835.
7. S.P. Meenakshisundaram, S. Parthiban, R. Kalavathy, G. Madhurambal,
G. Bhagavannarayana, S.C. Mojumdar, J. Therm. Anal. Calorim. 100 (2010) 831–
837.
8. C. Krishnan, P. Selvarajan, T.H. Freeda, C.K. Mahadevan, Physica B 404 (2009)
289–294.
9. S.S. Gupta, C.F. Desai, Cryst. Res. Technol. 34 (1999) 1329–1332.
10. Rajasekaran R., Mohan Kumar R., Jayavel R. and Ramasamy P. (2003), J.
Crystal Growth, Vol. 252, pp. 317-327.
11. Anand G, Gunasekaran S, Kumaresan S and Kalainathan S , Adv. Appl. Sci.
Res., 2011, 2 (3):550-557.
12. Boomadevi S., Mittal H.P. and Dhanasekaran R. (2004),J. Crystal Growth, Vol.
261 pp. 5562.
13. Gopinath S, Barathan S, Rajasekaran R , J Therm Anal Calorim (2012)
109:841–845.
323
THERMAL AND ACOUSTICAL STUDIES ON SOME
LIQUID ALKALI METALS *P. RAMADOSS, 1V. K. BHAVANISATHIYA
*Asst. Professor, P.G. and Research Department of physics, Govt. Arts College,
Tiruvannamalai-606 603. 1Asst. Professor, P.G. and Research Department of physics,
Shanmuga Industries Arts & Science College,
Tiruvannamalai-606 601.
ABSTRACT
Measurements of sound velocity in solids give useful information regarding
Strength, structure and interaction. In present study using elastic constant
at room temperature has been used to calculate sound velocity at various
direction there by Debye temperature. Mean sound velocity at liquid state has also
been calculated and strength of interaction for Ni, Fe, Ag, Cu, K, Na, Zn and Cd
is study. Heat of fusion, thermal Conductivity have been calculated for above
liquid metals. The results are analyzed.
INTRODUCTION:
Solids are characterized by greater binding forces between atoms than liquid
and gaseous. Using measured ultrasonic velocity in solids, electron-phonon,
phonon-phonon interaction, thermoelastic relaxation, lattice imperfections, grain
boundary losses are explained(1-3). Sound Velocity measurement in solid, liquid
mixtures and solution has been Used with allied parameters to calculate the bulk
properties of the medium (4-5). In solids,sound velocity is effectively used to get
some useful parameters which are not easily got from other means. They are Debye
temperature specific heat, lattice energy etc., at any state of physical condition
(6-8).Thermodynamic properties of liquid metals are calculated using varies
methods(9-10). The properties are entropy, specific heat, isothermal compressibility,
internal energy Helmholtz free energy ect., (11-12) Using these properties
electron-phonon and phonon-phonon interaction, transport properties, diffusion Co-
324
efficient are discussed. In the present investigation the following liquid metals have
been chosen for the study. They are Ni, Fe, K, Ag, Na, Zn, Cu and Cd.
THEORY AND CALCULATIONS:
Debye temperature is the only parameters which describes the properties
remarkably well(16), So it is useful to find as
θD = h/kB [9N/4πv(1/C13 + 2/Cs3)] 1/3
h = Planck’s constant (JS)
KB = Boltzmann constant (JK-1)
N = Avagataro number (mol-1)
V = Molar volume (X 103 mol)
Cl = longitudinal velocity (m/s)
Cs = shear velocity (m/s) and specific heat is related with θD as follows
Cv = (12/5) π4R (T/θD)3J/mol
R = Gas Constant (JK-1 mol-1)
T = Temperature (k)
Cv = Specific Heat Capacity (J/K mol)
The heat of fusion be calculated using the relaxation times at melting
temperature and given temperature as (14)
τm = τTeH/KT
τm&τT = Relaxation time at melting & room temperature (s)
T = Temperature (k)
H = Heat of fusion (KJ/mol)
K = Boltzsmann constant (JK-1)
325
In sound velocity in solid can be calculated using elastic constant an (10)
Cl = √﴾C11/ρ﴿
Cs = √﴾C44/ρ﴿
Where,
ClCs = Longitudinl and shear velocity (m/s)
C11,C44 = Elastic constant X 1010(N/m2)
ρ = density (kg/m3)
In expansion of coefficient in liquid can be calculated using Elastic constant.
KB θ 3 4 πv
-------- X ------- = Um
h 9N
Where,
KB = Boltz’smann constant (Jk-1)
θD = Debye temperature (k)
h = Planck’s constant (Js)
N = Avagodaros number (mol-1)
V = Molar volume (x103 mol)
V – V0
∆V = -------------
V0
∆V = Free volume (m3/mol)
326
V = Molar volume (x103 mol)
Vo = Melting volume (k)
3∆V 1/3
R = ------
4πN
V = Free volume (m3/mol)
N = Avagodaros number (mol-1)
R = Radius (A0)
TABLE: 1
Elastic constant, density, boiling temperature, and acoustical parameters of
Nickel, Iron, silver, sodium, copper, potassium, zinc and cadimum.
Symbols and their meaning used in table: 2
C11 & C44 = Elastic constant (1x 1010N/m2)
ρ = Density (kg/m3)
α = Expansion of coefficient (x10-6k)
TABLE: 2
Mechanical, thermal and acoustical parameters of Nickel, Iron, Silver,
Sodium, Copper, Potassium, Zinc and Cadmium.
Symbols and their meaning used in Table 2;
C11 & C44 = Elastic constant (1X1010N/m2)
ρ = Density (kg/m3)
C1&Cs&Cm = Longitudinal, shear and mean sound velocities (m/s)
327
θDR & θDM = Debye temperature at room temperature and melting Temperature (k)
H = Heat of fusion (KJ/mol)
ρT = Melting temperature (k)
V = Molar volume (kg)
Um = Melting at temperature (k)
C = Ratio between mean sound velocities and melting at
Um = Temperature (m/s)/K
ΔV = Free volume (m3/mol)
RA0 = Radius (A0)
Result and Discussion:
Table 1, gives a elastic constant C11 and C44, density, Co-efficient of thermal
expansion and Boiling temperature. For Ni, Fe, Ag, Cu, K, Na, Zn, and cd(15).
Table: 2, gives calculated Values at Normal and liquid temperature. They are
sound Velocity, Debye temperature, density, Molar Volume, change of Molar
volume, Lattice energy, Radius of empty space.
The sound velocity at normal temperature is greater than boiling
temperature, and Debye temperature at normal temperature is greater than at liquid
state. The ratio between mean sound velocity at normal and mean sound velocity
boiling at temperature is greater than the density higher than the liquid state
interaction between the atoms (i.e),Cadmium(Cd) in normal state is as highest
strength of the interaction at normal then liquid and sodium(Na), as lowest strength
of interaction at normal this reflects ΔV, excess volume, Radius of empty space.
Using Debye relaxation time, heat of fusion been calculated. The calculated
values agree with literature value.
328
TABLE-2 ACOUSTICAL AND THERMAL PROPERTIES OF SOME
ALKALI LIQUID METALS
Syst
em
Cl Cs Cm θD θ*DM Hf ρT V Um Cm/Um ΔV RA
0
Ni 53963 3832.1 4152 557.5 192.5 15.4
(17.8)
7810 7.517 1499 2.769 0.9704 0.7274
Fe 5561.3 3938.1 4269 558.3 299.14 9.37
(13.81)
6980 8.001 2379 1.7941 0.8955 0.7081
Ag 3431.5 2092.3 2310 267.26 103.17 9.76
(11.28)
9320 6.818 778 2.969 1.3760 0.8168
Cu 4335.2 2900.8 3169 414.2 164.99 10.37
(13.26)
8020 7.925 1308 2.422 0.8304 0.6905
K 2312.7
5
1738.7 4621 131.36 97.4 8.47
(2.33)
0.82
8
47.39
3
1401 2.870 1.925 0.9144
Na 2760.6 2080.8 2282 195.3 149.60 0.83
(2.60)
0927 24.80
0
1735 1.315 1.130 0.7652
Zn 4790.2 2332.1 2620 314.5 291.30 0.44
(7.32)
657 9.949 2491 1.0317 0.786 0.6780
Cd 3628.6 1523.2 7996 300.0 184.75 1.31
(6.21)
7996 14.05
7
1773 4.509 1.067 0.7496
Conclusion:
Heat of fusion, Debye temperature at liquid state, Mean sound velocity liquid
state have been calculated theoretically for Ni, Fe, Ag, Cu, K, Na, Zn, and Cd.
329
REFERENCES:
1. W.P Mason, piezoelectric crystals and their application to ultra sound, D.
VanNortrand and Co., Privator (1950),479.
2. W.P Mason physical acoustics Vol III B academic press. Inc..Newyork(1965)
237.
3. W.P Mason & T.B Bateman T.B.J Acoustics Soc., am 40 (1966) 852.
4. Richaards W.T and Reid J.A. Chem. Phys.,1 (1933) 144.
5. Rama Rao, Current science,23 (1954) 325.
6. Reddy T.S and Rao N. Acoustica,61 (1989) 225.
7. Mason W.P & Bateman T.B.J. Acoust. Soc. Am. 6(1964) 645.
8. Reddy R.R. etal Ind J.pure Ultrason, 19 (1997)113.
9. Wei- Qiang Han and Alex Zettl., Appl.Phys. Lett. 80 (2002).
10. Pandey D.K. Singh D and Yadav R.R. Appl. Acoustics 68 (2007) 766.
11. Pandey P.K. Yadawa P.K. Yadav R.R. Materials letters 61 (2007) 5194.
12. J. Blitz, Fundamentals of ultrasonic, Butler worth’s, 1967 London 150.
13. Mason W. P. Physical Acoustics. Vol-II(B) Academic press 1965 (Newyork)
1965.
14. Frenkel J. Kinetic theory of Liquids, Dover Publication.Newyork (1755).
15. G.W.C. Kaye S.T.H. Laboy Tablas & Physical chemical constants 13th ED
Longmans Londan (1968).
16. Durai & Ramadoss P. Bullekin of pure Appl. Science 22(D)(2003) 145.
330
HYDROTHERMAL SYNTHESIS OF CERIUM OXIDE NANO PARTICLES
P.Vijayashanthi1, A.Aarthi1, S. Shanmuga Sundari1*
1Department of Physics, PSGR Krishnammal College for Women, Coimbatore, India.
Corresponding author mail id : [email protected]
ABSTRACT
Nano particles have attracted much attention due to the physical and chemical
properties that are significantly different from those of bulk materials. Cerium oxide
is the most abundant element in rare earth family. In the present work Cerium oxide
(ceria) nano particles were prepared by hydrothermal method. Cerium nitrate hexa
hydrate is taken as starting materials and Ammonia as a precipitation agent. Citric
acid is used as size controlling agent. The additives have a strong effect on the
particle size and particle size distribution. Cerium nitrate was dissolved in Distilled
water. And citric acid was added. At the beginning of reaction, The transparent
yellow color came out in the solution subsequently it turned into dark brown color .
The time required for completing the reaction was 8 hrs. The solution was
transferred into Teflon autoclave set up and maintained at 430 K for 24 hrs and then
centrifuged. Finally, centrifuged particles are dried at 353 K. The prepared CeO2
nano particles structure has been analyzed for structural, surface and optical
characteristics. Structure of the prepared particles was examined by XRD and FTIR.
The surface morphology and optical characteristics was studied using SEM, UV and
PL respectively.
Keyword: ceria, hydrothermal, UV, PL, XRD
1. INTRODUCTION
Cerium oxide (CeO2) is a major compound in the useful rare earth family and
has been applied practically in glass-polishing materials, sunscreens, solid
electrolytes and filters, buffer layers with silicon wafer, gas sensors, catalysts in the
fuel cell technology, catalytic wet oxidation, engine exhaust catalysts, NO removal,
photocatalytic oxidation of water and as an ultraviolet absorbent and automotive
exhaust promoter [1-5]. In recent years, ultrafine nanometer-sized particles attracted
much attention due to their physical and chemical properties, which are significantly
331
different from those of bulk materials. Fine particles of cerium oxide with a very
small size have the potential of becoming a very useful material as a fine UV
absorbent and high-activity catalyst [6, 7]. Numerous techniques have been proposed
to synthesize nano-sized CeO2 particles with promising control of properties, such as
hydrothermal, reverse micelles, sonochemical, pyrolysis and homogeneous
precipitation [8,9]. In the present work ceria nanoparticles were prepared by
hydrothermal method.
2. EXPERIMENTAL TECHNIQUE
In the present work ceria nanoparticles are prepared by hydrothermal
method. Cerium nitrate hexahydrate was taken as a precursor, ammonia as a
precipitating agent and citric acid as a size controlling agent. In the room
temperature, Cerium nitrate hexahydrate and citric acid was dissolved in distilled
water and 15 ml of ammonia was added the solution. Suddenly a white precipitate
occurs and as time passed it turns to violet and at the end of the reaction the solution
turns to dark brown color. The brown colored solution shows the Brownian motion
under Green laser. In the whole process the rpm rate was fixed to 850 rpm. The final
solution was transferred to Teflon coated autoclave and heated to 550 K for 12
hours. After that the solution was centrifuged for 45 min using water and ethanol
alternatively. Centrifuged particles were dried at 350 K for 5 hrs, particles are brown
in color. Prepared Ceria particles are characterized by XRD and FTIR for structural
and Optical studies using PL and UV-Vis spectrographs. Surface morphology was
investigated by SEM.
3. RESULTS AND DISCUSSION
3.1.Structural Analysis
3.1.1. X- ray diffraction analysis
Figure 1. XRD pattern of CeO2 nanoparticle
332
XRD pattern was recorded at room temperature from 10o to 80o, 2θ range and
it is shown in figure 1. The high intensity peaks were observed at 28.51, 33.08,
47.44, 56.32, 76.63 respective to the (111), (200), (220), (311), (331) crystal planes.
The crystal planes were in well accordance with JCPDS No: 34-0394 of CeO2
crystal. The diffraction peaks in these XRD spectra indicates the pure cubic fluorite
structure. The average particle size (D) is calculated using scherrer formula,
Ʈ = k /β cos θ (1)
where, τ is mean size of the ordered (crystalline), K is the shape factor, λ is the X-ray
wavelength, β is the line broadening at half the maximum intensity (FWHM) in
radians and θ is the Bragg angle. The crystallite size was found to be in the range
from 7.9-8.6 nm. The value of lattice parameter a calculated from the XRD pattern
and it is found to be 5.4192 Å
3.1.2. Fourier transforms infra-red spectra
Figure 2. FTIR spectrum of CeO2 nanoparticle
The spectrum was recorded in the wave number range of 400-4000 cm-1 at room
temperature as shown in figure 2. The broad absorption band located around 3447
cm-1 corresponds to the O-H stretching vibration of residual water and hydroxyl
groups, while the absorption band at 1620 cm-1 is due to the scissor bending mode of
333
associated water. The band at 703 cm-1 corresponds to bending mode of (C=O) in an
oxalate group. The band position and assignments are given in table 1.
Table 1. Peak assignments of FTIR spectra of ceria nano particles.
WAVE NUMBER (cm-1) BAND ASSIGNMENTS
3521 O-H stretching
3447 O-H stretching vibration of residual water
3386 Bending O-H in water
2884 C-H bonds of the organic compounds
1620 Scissor bending vibration of O-H in water
1529 Vibrations of carbonate group
1374 Vibrations of NO3-1ions
1216 vibration modes ofSO42-
703 Bending mode of C=O in an oxalate group.
510 Stretching vibration
3.2. Surface Analysis – Scanning Electron Micrograph
Figure 3. SEM image of CeO2 nanoparticle
334
Surface and morphological characterization of cerium oxide nanoparticles were
carried out using scanning electron microscopy. Nanosized spherical shaped
CeO2 particles obtained was confirmed. The mean size of the particles was found to
be 10 nm. SEM of cerium oxide nanoparticles is shown in Figure 3.
3.3. Optical Characterization
3.3.1. UV-Vis spectral Analysis
Figure 4. UV spectrum of CeO2 nanoparticle
335
Figure 5. Direct bandgap graph of CeO2 nanoparticle
The UV–visible absorption spectra was recorded from 200 nm to 1200 nm of the
CeO2 and is shown Figure 4. The sample shows a strong absorption below 400 nm
with a well-defined absorbance peak at around 222. In the visible range the sample is
don’t have any absorption. The direct band gap can be determined by fitting the
absorption data to the direct transition equation (2), by extrapolating of the linear
portions of the curves to absorption equal to zero.
αhν = ED (hν − Eg)1/2 (2)
where α is the optical absorption coefficient, hv is the photon energy, Eg is the direct
band gap, and ED is a constant .The estimated band gap of the CeO2 sample is 2.74
eV. The corresponding results are shown in figure 5.
3.3.2. Photo Luminescence analysis
Figure 6. PL spectrum of CeO2 nanoparticle
The PL (figure 6) of the CeO2 mainly consists of four emission bands : a strong
broad emission band at ~ 406 nm (3.06 eV), a strong blue band at 420 nm (2.95eV),
blue gand at ~483 nm, (2.57 eV), and a weak green band at 530 nm (2.34 eV).
336
4. CONCLUSION
Cerium oxide nano particles were prepared by hydrothermal method. The average
particle size (7 nm) were calculated from XRD and SEM and they are in
accordance with each other. The absence of impurity peaks in XRD confirms the
pure formation of ceria. Optical bandgap was calculated from UV-Vis spectra.
REFERENCES
[1] Lunxiang Yin, Yanqin Wang, Guangsheng Pang, Yuri Koltypin, and Aharon
Gedan ken, Sonochemical Synthesis of Cerium Oxide Nanoparticles—Effect of
Additives and Quantum Size Effect, Journal of Colloid and Interface Science
246, 78–84 (2002).
[2] T. Masui, H. Hirai, N. Imanaka, G. Adachi, Synthesis of cerium oxide
nanoparticles by hydrothermal crystallization with citric acid, Journal of
Materials Science Letters 21, 2002, 489– 491
[3] Huey-Ing Chen, Hung-Yi Chang, Synthesis of nanocrystalline cerium oxide
particles by the precipitation method, Ceramics International 31 (2005) 795–802
[4] Huey-Ing Chen, Hung-Yi Chang, Synthesis and characterization of
nanocrystalline cerium oxide powders by two-stage non-isothermal precipitation,
Solid State Communications 133 (2005) 593–598
[5] Boro DjuricÏic and Stephen Pickering, Nanostructured Cerium Oxide:
Preparation and Properties of Weakly-agglomerated Powders, Journal of the
European Ceramic Society 19 (1999) 1925-1934
[6] Jiaoxing Xu, Guangshe Li, Liping Li, CeO2 nanocrystals: Seed-mediated
synthesis and size control, Materials Research Bulletin 43 (2008) 990–995
[7] M.J. Godinho , R.F. Gonçalves , L.P. S Santos , J.A. Varela , E. Longo , E.R.
Leite. Room temperature co-precipitation of nanocrystalline CeO2 and
Ce0.8Gd0.2O1.9−δ powder, Materials Letters 61 (2007) 1904–1907
[8] Jin-Seok Lee, Sung-Churl Choi, Crystallization behavior of nano-ceria powders
by hydrothermal synthesis using a mixture of H2O2 and NH4OH, Materials
Letters 58 (2004) 390– 393
[9] Richard I. Walton, Solvothermal synthesis of cerium oxides, Progress in Crystal
Growth and Characterization of Materials 57 (2011) 93–108