Theoretical calculations of self-broadening coefficients in the nu(6) band of CH3Br

摘要

A semiclassical impact theory based upon the Anderson-Tsao-Curnutte formalism has been used to calculate the self-broadening coefficients in the P-P-, (P)Q-, R-P-, P-R-, (R)Q- and R-R-branches of the nu(6) band of (CH3Br)-C-12-Br-79 and (CH381)-C-12 Br near 10 mu m. Comparisons have then been performed with the extensive set of previous measurements 3 (Jacquemart et al., 2007). The intermolecular potential used, involving the overwhelming electrostatic contributions, leads to larger results than the experimental data for middle J values. By arbitrarily limiting. the integration of the differential cross-section to an impact parameter equal to 29 angstrom. quite satisfactory results have been obtained, and the J and K dependences are in reasonable agreement with those observed experimentally. The theoretical results are, on the whole, slightly larger for (CH3Br)-Br-78 than for CH381 Br and for same J and K initial states of the transitions they depend on the sub-branch considered. These differences and dependencies were not observed in the previous measurements due to scatter in the experimental data. Finally, the theoretical results obtained for all sub-branches of (CH3Br)-C-12-Br-79 and (CH3Br)-C-12-Br-81 are given as supplementary materials of this paper.