Infrared measurements and rovibrational study of the v₇ band of vinyl chloride by diode laser spectroscopy

Abstract

The gas-phase infrared spectra of natural CH 2Ð Ð CHCl and monoisotopic CH 2 Ð Ð CH 37 Cl (isotopic purity, 95%) have been investigated in the t 7 band region near 1030 cm -1 , at Doppler-limited resolution, employing a tunable diode laser spectrometer. This vibration of symmetry species A Â is expected to give rise to an a/b hybrid band, with a predominant contribution of the a-type component. A rovibrational analysis led to the identi® cation of more than 1100 (J < 51, K a < 12) and 1000 (J < 47, K a < 12) transitions belonging to the 35 Cl and 37 Cl isotopomers, respectively. The band was found to be a ected by di erent perturbations, and avoided crossings due to the second-order a-Coriolis resonance with the t 9 + t 12 combination also were observed. After using Watson's A-reduction Hamiltonian in the I r representation, the assigned transitions provided a set of e ective upper state constants for both the isotopic species.