Measurements and calculations of Ar-broadening and shifting parameters of CH3F transitions in the ν6 band

Abstract

The line broadening and first shifting coefficients of CH3F for 434 lines in the ν6 vibrational band induced by argon at seven total pressures between 33 and 250 Torr have been recorded using the Fourier transform spectrometer Bruker IF125HR located at the LISA facility in Créteil. The measurements were performed at room temperature with a spectral resolution of 0.005 cm–1. The collisional line widths and shifts are obtained from the non-linear least-squares fitting techniques. A Voigt profiles model was used in the present analysis which appeared to properly model the observed molecular line shapes within the noise level. The calculations of the broadening and shifting coefficients γ0 and δ0 were performed in the framework of the semi-classical method using an exact isotropic trajectories and a Smith–Giraud–Cooper intermolecular potential model. The calculated values of the broadening and shift coefficients show a quite good agreement with experimental data. The data obtained in the present work represent a significant contribution to the determination of shift and broadening coefficients of CH3F and complement the list of line positions, intensities and broadening coefficients generated in the literature, thus providing useful spectroscopic information for atmospheric remote sensing of CH3F.