DIODE-LASER SPECTRUM AND ROVIBRATIONAL ANALYSIS OF THE NU-6 BAND OF VINYL FLUORIDE

The vibration-rotation spectrum of CH2=CHF has been investigated in th e nu6 band region around 1305 cm-1 at Doppler limited resolution using a tunable diode laser spectrometer. The measurements have been perfor med at low temperature (240 K) to decrease hot band interferences. Thi s fundamental of symmetry species A' gives rise to an a/b hybrid band, which was mainly composed of a-type transitions. Both J and K structu res have been resolved in the (Q)Q(K)(J) subbranches and the rovibrati onal analysis in the P, Q, and R branches has led to the identificatio n of more than 1000 lines with J less-than-or-equal-to 43 and K(a)' le ss-than-or-equal-to 14. The nu6 band is affected by first-order b-type and second-order a-type Coriolis resonances with the nu9 + nu11 combi nation, and the perturbation effect has been found stronger for the K( a)' = 11 level. About 870 transitions free of major resonance contribu tions were fitted using Watson's A-reduction Hamiltonian in the I(r) r epresentation, and a set of effective rotational and quartic centrifug al distortion constants was determined for the upsilon6 =1 state of CH 2=CHF.