HIGH-RESOLUTION FTIR SPECTRUM OF VINYL FLUORIDE NEAR 9 MU-M - ROVIBRATIONAL ANALYSIS OF THE NU(7) BAND

The Fourier transform infrared spectrum of CH2=CHF has been investigat ed in the nu(7) band region around 1155 cm(-1) at a resolution of abou t 0 . 002 cm(-1). This fundamental of symmetry species A' yields an a/ b hybrid band with a prevalent contribution of the a-type component. T he band is affected by first-order b-Coriolis resonance with the nu(9) + nu(12) combination, and the interactions are markedly stronger for the K-a' = 11 and 12 levels; local perturbations with crossings due to higher-order a- and b-Coriolis resonances have also been observed. Th e rovibrational analysis led to the identification of more than 2900 l ines of nu(7) with J less than or equal to 64 and K-a less than or equ al to 18, while no features were detected for the nu(9) + nu(12) band. Using Watson's A-reduction Hamiltonian in the I-r representation, the present ground state combination differences combined with available microwave data led to improved sextic distortion terms for the ground state. Of the assigned lines, 2329 free of major resonance contributio n provided excited stale constants for the nu(7) band. Furthermore, fr om the perturbation effects near the crossings, some parameters for th e nu(9) + nu(12) combination have been determined.