High-resolution FTIR spectra of CH2 = CClF in the 930-1050 cm−1 region

Abstract

The gas-phase infrared spectra of natural CH2 = CClF have been measured in the v 6 and 2v 12 band regions (930–1050 cm−1) by high-resolution Fourier transform spectroscopy at room temperature. 1-Chloro-1-fluoroethylene is a planar asymmetric rotor (κ = −0.54) belonging to the symmetry point group Cs and the vibrations investigated of symmetry species A′ give rise to a/b-hybrid bands with contributions of comparable intensity from both the components. The rovibrational analysis of the fine structure led to the identification of 1894 (J ⩽ 73, Ka ⩽ 20) and 718 (J ⩽ 53, Ka ⩽ 8) transitions for the v 6 and 2v 12 bands of the 35Cl isotopic species, respectively. Using the Watson's A-reduction Hamiltonian in the Ir representation a set of accurate spectroscopic parameters for both the excited states u 6 = 1 and u12 = 2 of 35Cl has been obtained for the first time. Transitions of 37Cl isotopomer could also be assigned in the Q branch region of the 2v 12 overtone; the determined band origin shift of 0.782 cm−1 towards the lower wavenumbers led to describing the v 12 fundamental as a vibration mainly involving the CFCl bending motion.