Oxygen- and air-broadening coefficients for the CH 3 I ν 6 fundamental at room temperature
Résumé
CHI-oxygen line-broadening coefficients at 296 K are calculated for the RR, PR, RP, PP, RQ and PQ sub-branches of the band in a wide range of rotational quantum numbers (, by a semi-classical and a semi-empirical methods. The computed values compare very favourably with the available experimental data and therefore can be safely employed as estimates of broadening coefficients missing in databases for high and . The theoretical data for CHI-O are further combined with the previously calculated room-temperature CHI-N line-broadening coefficients to obtain the air-broadening values required for atmospheric applications. The calculated results demonstrate an excellent consistency with both existing sets of CHI-air measurements. As the vibrational dependence of CHI oxygen-broadening coefficients is shown to be small, similarly to the nitrogen-broadening case, the CHI-O and CHI-air line-broadening coefficients calculated for the fundamental can be used for other perpendicular and parallel bands.