HIGH-RESOLUTION FTIR SPECTRUM OF THE NU-5 BAND OF 1,1-DIFLUOROETHYLENE AROUND 550 CM-1

The infrared spectrum of CF2CH2 recorded in the range 400-4000 cm-1 with a Fourier transform infrared spectrometer has been studied in the ν5 region. This fundamental approximately described as a CF2 scissor mode gives rise to an a-type band showing in most regions of the spectrum distinct patterns characteristic of molecules approaching the oblate symmetric top limit. The rovibrational analysis extended to the P, Q, and R branches led to the identification of about 3000 transitions covering J and Ka values up to 70 and 46, respectively. Using Watson's A-reduction Hamiltonian the assigned transitions provided a set of accurate rotational and centrifugal distortion constants for the first excited vibrational state of the ν5 band of CF2CH2. © 1991.