Xe-broadening coefficients of ¹²CH₃D: A test of theoretical line shapes

We present the Xe-broadening coefficients for six lines belonging to the ν₃ band of ¹²CH₃D measured at room temperature with a diode-laser spectrometer. The collisional widths are obtained from least-squares fitting of each absorption line with theoretical line shapes. We used the well-known Voigt profile, the soft and hard collision models considering the collisional narrowing and also line shapes taking into account the speed dependence of the collisional cross-section. The results derived by these different models are compared with each other and with theoretical broadening coefficients. The calculations are based on a semiclassical impact formalism that includes the atom-atom Lennard-Jones potential for CH ₃D-Xe interactions in which CH₃D is considered as a linear molecule.