High-resolution (0.0013 cm-1) infrared spectra have been recorded for trans,trans-1,4-difluorobutadiene (ttDFBD) and cis,cis-1,4-difluorobutadiene (ccDFBD). The rotational structure in two C-type bands (ν10 and ν12) and one A-type band (ν22) for ttDFBD and in two C-type bands (ν11 and ν12) for ccDFBD has been analyzed. Ground state and upper state rotational constants, except for ν10 of ttDFBD, have been fitted. Band centers are 934.1 cm-1 (ν10), 227.985 cm-1 (ν12), and 1087.919 cm-1 (ν22) for ttDFBD. Band centers are 762.891 cm-1 (ν11) and 327.497 cm-1 (ν12) for ccDFBD. The small inertial defects in the ground state confirm that both isomers are planar. Obtaining the ground state rotational constants for the two isomers of DFBD is a first step toward determining their semi-experimental equilibrium structures. © 2009 Elsevier Inc. All rights reserved.
Craig, N. C., Moore, M. C., Neese, C. F., Oertel, D. C., Pedraza, L., & Masiello, T. (2009). High-resolution infrared spectra of the two nonpolar isomers of 1,4-difluorobutadiene. Journal of Molecular Spectroscopy, 254(1), 39–46. https://doi.org/10.1016/j.jms.2009.01.003