ANALYSIS OF THE ROTATIONAL STRUCTURE IN THE HIGH-RESOLUTION INFRARED SPECTRA OF cis,cis- AND trans,trans-1,4- DIFLUOROBUTADIENE-1-d 1 AND trans,trans- 1,4-DIFLUOROBUTADIENE-1,4-d 2 NORMAN C. CRAIG , YIHUI CHEN, YUHUA LU, CHRISTOPHER F. NEESE, and DEACON J. NEMCHICK, Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074. THOMAS A. BLAKE, Pacific Northwest National Laboratory, Richland, WA 99252.
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ANALYSIS OF THE ROTATIONAL STRUCTURE IN THE HIGH-RESOLUTION INFRARED SPECTRA OF cis,cis- AND trans,trans-1,4- DIFLUOROBUTADIENE-1-d 1 AND trans,trans-
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ANALYSIS OF THE ROTATIONAL STRUCTURE IN THE HIGH-RESOLUTION INFRARED
SPECTRA OF cis,cis- AND trans,trans-1,4-DIFLUOROBUTADIENE-1-d1 AND trans,trans-
1,4-DIFLUOROBUTADIENE-1,4-d2
NORMAN C. CRAIG, YIHUI CHEN, YUHUA LU, CHRISTOPHER F. NEESE, and DEACON J. NEMCHICK, Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074.
THOMAS A. BLAKE, Pacific Northwest National Laboratory, Richland, WA
99252.
Goal and Prior Knowledge • Semiexperimental (SE) structures for the nonpolar cis,cis
and trans,trans isomers of 1,4-difluorobutadiene (DFBD).• GS rotational constants for the 2-d1 isotopologues are
known.a
• GS rotational constants for the singly substituted 13C and 18F species can be predicted well from QC calculations.
• An SE structure for polar cis,trans-DFBD is known from MW spectroscopy.b
a Craig, N. C.; Easterday, C. C.; Nemchick, D. J.; Williamson, D. F. K.; Sams, R. L. J. Mol. Spectrosc. 2012, 272, 2.
b Demaison, J. F.; Craig, N. C. J. Phys. Chem. A 2011, 115, 8049.
cis,cis-DFBD-1-d1 C-type band for 19
Detail of P branch. S/N marginal. Loomis-Wood pattern recognition is essential.
Loomis-Wood Display for C-type band (19) of ccDFBD
a Calculated with the MP2/cc-pVTZ model; alphas, Peter Groner's VIBROT program. b Scale factors for obs/calcd are 0.9935079 for A0, 1.0072867 for B0, and 1.0059332 for C0.
Conclusions
GS rotational constants have been obtained for the 1-d1 species of cis,cis and trans,trans-DFBD from the analysis of rotational structure in IR spectra.
GS rotational constants for the corresponding 2-d1 species were found previously.
Good GS rotational constants for singly substituted 13C and 18F species can be predicted with scaling.
The stage is set for determining semiexperimental equilibrium structures of the cis,cis and trans,trans isomers of DFBD.
Acknowledgements
Peter Groner, University of Missouri at Kansas City