Analysis of O₂-broadening of ¹²CH₃F lines in the 6.8 μm spectral region

Using a tunable diode-laser spectrometer, we have measured the O-broadening coefficients for 45 lines of methyl fluoride in the P and R branches of the ν parallel band, and in the P, Q, R, P, Q, and R branches of the ν 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. 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 ν and ν bands are in overall agreement with the experimental data,