Collisional-Broadening Coefficients in the nu6 Band of 12CH3F Perturbed by Ar.

Ar-broadening coefficients are measured for 29 lines of CH3F in the RQ0 and RQ6 branches of the nu6 band, using a tunable diode-laser spectrometer. The collisional widths obtained by fitting Rautian profiles to the measured shapes of the lines are significantly larger, especially for the overlapping lines at low-J values, than those obtained from Voigt profiles. The broadening coefficients for the lines belonging to the same low-J transitions (J = 7-10) appear to be greater in the RQ0 branch than in the RQ6 branch. Comparisons have been made with calculated results based on a semiclassical model including adjustable potential parameters. Copyright 1998 Academic Press.