Broadening coefficients of methyl iodide vibrotational lines induced by nitrogen, oxygen and air pressure
J.V. Buldyreva1, L.A. Troitsyna1, A.S. Dudaryonok2, N.N. Lavrentieva2
1Institute UTINAM, Besanson, France
2V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: line profile, line-broadening, symmetric top, methyl iodide
Abstract
The nitrogen-, oxygen and air-broadening coefficients of CH3I lines in the n6 band (RP-, PP-, RQ-, PQ-, RR-, and PR-sub-branches) are calculated at room temperature with the rotational quantum numbers 0 ≤ J ≤ 70, 0 ≤ K ≤ 20. Calculations are performed by two methods: the semi-classical method with exact trajectories, adapted for the case of an absorbing molecule such as a symmetric top, colliding with a diatomic homonuclear partner, and the semi-empirical method based on the impact semi-classical theory and using an empirically adjusted factor for the efficiency functions. When comparing with recently published experimental data, a good agreement was obtained for the semi-empirical approach, so that the half-widths can be calculated by this method for reliable use in atmospheric applications.
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