Analysis of O2-Broadening of 12CH3F Lines in the 6.8-µm Spectral Region.

Using a tunable diode-laser spectrometer, we have measured the O2-broadening coefficients for 45 lines of methyl fluoride in the QP and QR branches of the nu2 parallel band, and in the PP, PQ, PR, RP, RQ, and RR branches of the nu5 perpendicular band. These lines with J values ranging from 1 to 23 and K from 0 to 9 (K </= J) are located in the spectral range 1416-1573 cm-1. The collisional halfwidths are obtained by modeling each spectral line with a Voigt and a Rautian profile. The noncorrelated Rautian model leads to larger values of broadening coefficients than the Voigt model. These coefficients have also been calculated from a semiclassical model in which the intermolecular potential includes electrostatic, induction, and dispersion energy contributions. The results in the P, Q, and R branches of the nu2 and nu5 bands are in overall agreement with the experimental data. Copyright 1998 Academic Press.