Semi-classical H-2-broadening coefficients of (CH3D)-C-12 rovibrational lines and their temperature dependence for planetary atmosphere modeling

Theoretical hydrogen-broadening coefficients and associated temperature exponents for (CHD)-C-12-D-3 (J, K) lines in parallel (Delta K = 0) bands are calculated by a semi-classical approach based on a rigorous consideration of the active molecule as a symmetric top, a model intermolecular potential comprising both short- and long-range interactions, and exact classical trajectories. The leading potential terms are shown to provide a realistic description of line broadening in comparison with scarce measurements available in the literature. The calculations performed for 296, 240 and 190 K are used to extract the line-width temperature dependence exponents for the typical temperature range of atmospheric interest similar to 200-300 K. Detailed P-Q-R-line lists are provided for large intervals of quantum numbers (0 <= J <= 20, 0 <= K <= J) requested for remote sensing of planetary atmospheres, in particular those of outer planets and their moons. With negligible vibrational dependence of CH3D line-widths and estimated as negligible their sub-branch dependence, these data can be also employed for perpendicular bands. (C) 2016 Elsevier Inc. All rights reserved.