Self-, air, and noble gas broadening in rotational-vibrational bands of SO 2 , H 2 S, and NO 2

Abstract

Beside the knowledge of line positions and strengths precise data on the line broadening are prerequisite for the analysis of atmospheric transmission spectra and the in-situ determination of trace gas concentrations. Moreover, experimental data on the line broadening provide information on the collision processes as origin of broadening and shift of absorption lines. In this paper result on the line broadening obtained with a pulse driven diode laser spectrometer are presented. Intensive studies of the self- broadening were carried out for the v 1 , v 3 , and v 1 plus v 3 bands of SO 2 , the v 1 , v 2 , v 3 , and 2v 2 bands of H 2 S, and the v 3 band of NO 2 in order to analyze the quantum number dependence of the broadening coefficients. For SO 2 a pronounced decrease of the broadening coefficients with increasing quantum number K a n was found. In the case of H 2 S the J n -dependence dominates, whereas in the case of NO 2 a trend is not obvious. To study the perturber dependence of the broadening, air, He, Ne, Ar, Kr, and Xe were included in the experiments. The tendencies observed for noble gas perturbers could be described theoretically with a modified Anderson-Tsao-Curnutte-theory.