JOURNAL OF MOLECULAR SPECTROSCOPY 176, 274– 279 (1996 ) ARTICLE NO. 0087 High-Resolution Infrared Emission Spectrum of NaF A. Muntianu, B. Guo, and P. F. Bernath Centre for Molecular Beams and Laser Chemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 Received September 25, 1995; in revised form December 4, 1995 The high-resolution infrared emission spectrum of sodium monofluoride has been recorded with a Fourier transform spectrometer. A total of 1131 of vibration–rotation transitions, from the £ Å 1 r 0 to £ Å 9 r 8 vibrational bands, have been assigned. The infrared data have been combined with existing microwave data in order to obtain improved spectroscopic constants, including Dunham Yij and Uij coefficients, for the X1 S / electronic ground state of NaF. 1996 Academic Press, Inc. INTRODUCTION An electron diffrac tion study of alkali fluoride vapor s ( 5) has also been completed. In addition, it should be men- Alkali halides are the classical examples of ionic bond- tioned that the spectroscopic constants of NaF are use- ing. These molecules have been extensively studied by ful in the study of reaction dynamics, such as the Na / many different methods. A review of the spectroscopic FCH 3 r NaF / CH 3 system (6). This paper represents the literature on NaF was published by Douay et al. (1) in first experimental study and analysis of the high-resolu- their diode laser measurements of the vibration–rotation tion Fourier-transform infrared emission spectrum of NaF. first overtone spectrum. Since that time, some ab initio The previous diode laser work (1) generated a very small calculations have been published (2, 3), as well as a refit data set since only a few R-branch lines were measured of the NaF data using analytical potential functions ( 4). for the D£ Å 2 overtone bands. FIG. 1. A portion of the R branch of vibration–rotation spectrum of NaF. The 1–0 and 2–1 bands are marked along with the Jvalue. 274 0022-2852/96 $18.00 Copyright 1996 by Academic Press, Inc. All rights of reproduction in any form reserved. AID JMS 6 50 / 6t0 421 03-18- 6 20:55:45 ms al AP: Mol S ec
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8/3/2019 A. Muntianu, B. Guo and P. F. Bernath- High-Resolution Infrared Emission Spectrum of NaF
OURNAL OF MOLECULAR SPECTROSCOPY 176, 274– 279 (1996)
ARTICLE NO. 0087
High-Resolution Infrared Emission Spectrum of NaF
A. Muntianu, B. Guo, and P. F. Bernath
Centre for Molecular Beams and Laser Chemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
Received September 25, 1995; in revised form December 4, 1995
The high-resolution infrared emission spectrum of sodium monofluoride has been recorded with a Fourier transformspectrometer. A total of 1131 of vibration–rotation transitions, from the £ Å 1 r 0 to £ Å 9 r 8 vibrational bands,have been assigned. The infrared data have been combined with existing microwave data in order to obtain improvedspectroscopic constants, including Dunham Y ij and U ij coefficients, for the X 1S/ electronic ground state of NaF. 1996
Academic Press, Inc.
INTRODUCTION An electron diffraction study of alkali fluoride vapors (5)has also been completed. In addition, it should be men-
Alkali halides are the classical examples of ionic bond- tioned that the spectroscopic constants of NaF are use-
ng. These molecules have been extensively studied by ful in the study of reaction dynamics, such as the Na /many different methods. A review of the spectroscopic FCH3 r NaF / CH3 system (6 ). This paper represents theiterature on NaF was published by Douay et al. (1) in first experimental study and analysis of the high-resolu-heir diode laser measurements of the vibration–rotation tion Fourier-transform infrared emission spectrum of NaF.
first overtone spectrum. Since that time, some ab initio The previous diode laser work (1) generated a very smallcalculations have been published (2, 3), as well as a refit data set since only a few R-branch lines were measuredof the NaF data using analytical potential functions ( 4). for the D £ Å 2 overtone bands.
FIG. 1. A portion of the R branch of vibration–rotation spectrum of NaF. The 1–0 and 2–1 bands are marked along with the J value.
274022-2852/96 $18.00
opyright 1996 by Academic Press, Inc.
All rights of reproduction in any form reserved.
AID JMS 6 50 / 6t0 421 03-18- 6 20:55:45 ms al AP: Mol S ec
8/3/2019 A. Muntianu, B. Guo and P. F. Bernath- High-Resolution Infrared Emission Spectrum of NaF
deviation of the fit of 0.587 was obtained with 38 parame- ACKNOWLEDGMENT
ers.We thank the Natural Sciences and Engineering Research Council of
Dunham Y ij coefficients, listed in Table 3, were obtained Canada for support.
by fitting the data set to the energy level expression (11)REFERENCES
1. M. C. Douay, A. M. R. P. Bopegedera, C. R. Brazier, and P. F. Bernath,
Chem. Phys. Lett. 148, 1–5 (1988).
2. J. Modisette, L. Lou, and P. Nordlander, J. Chem. Phys. 101, 8903– E ( £, J ) Å ∑i, j
Y ij £ / 1
2i [ J ( J / 1)] j.
8907 (1994).
3. I. Garcı Ba-Cuesta, L. Serrano-Andres, A. Sanchez de Meras, and I.
Nebot-Gil, Chem. Phys. Lett. 199, 535– 544 (1992).
4. J. A. Coxon and P. G. Hajigeorgiou, Chem. Phys. 167, 327– 340 (1992).
5. J. G. Hartley and M. Fink, J. Chem. Phys. 89, 6058–6063 (1988).A total of 14 Dunham Y ij constants were necessary to repro-6. J. C. Polanyi, J. X. Wang, and S. H. Yang, Israel J. Chem. 34, 55–58duce the data with a reduced standard deviation of 0.539.
(1994).These constants are in agreement with, but superior to, those
7. D. R. Lide (Ed.), ‘‘Handbook of Chemistry and Physics,’’ 74th ed.eported by Douay et al. (1). Finally, to minimize the number CRC Press, Boca Raton, FL, 1993.
of free parameters, a mass-reduced Dunham fit (mNa Å 8. R. B. Le Blanc, J. B. White, and P. F. Bernath, J. Mol. Spectrosc. 164,
574–579 (1994).22.98977, mF Å 18.998403) was carried out, varying only9. R. K. Bauer and H. Lew, Can. J. Phys. 41, 1461–1469 (1963).he U i0 and U i1 constants (12). All higher order U ij ( j ú 1)
10. S. E. Veazey and W. Gordy, Phys. Rev. A 138, 1303–1311 (1965).constants were constrained by analytical relationships (12).
11. J. L. Dunham, Phys. Rev. 41, 721–731 (1932).n this case, nine parameters reproduced the data with a 12. H. G. Hedderich, M. Dulick, and P. F. Bernath, J. Chem. Phys. 99,
8363–8370 (1993).tandard deviation of 0.741 (see Table 4).