Air-broadening coefficients of CH_3 ~(35)Cl and CH_3 ~(37)Cl rovibrational lines and their temperature dependence by a semi-classical approach

摘要

Air-broadening coefficients and associated temperature exponents for CH_3 ~(35)Cl and CH_3 ~(37)Cl (vib)rotational transitions of QR-type branches are calculated by a semi-classical approach previously validated on extensive room-temperature measurements. Contrary to the theoretical methods used in the literature for the CH_3X-type absorbers, the active molecule is rigorously treated as a symmetric top with long- as well as short-range interactions and the exact classical trajectories are employed for the relative molecular motion. Analogous parameters additionally computed for N_2- and O_2-broadening provide a very favorable comparison with available low-temperature experimental results and ensure the reliability of the reported values in the interval of atmospheric interest 200-300K. Numerical data for 0≤J≤70 and K≤20 are given as supplementary materials for use in atmospheric applications and spectroscopic databases.