Noble gas pressure broadening in the v1 and v3 band of SO 2 studied with IR tunable diode laser spectroscopy

Abstract

Detailed investigations of the pressure broadening of SO 2 for collisions with the noble gases He, Ne, Ar and Kr are presented. The broadening coefficients of 14 lines in the v 1 band near 1151 cm −1 (13 ⩽ J″ ⩽ 44, 3 ⩽ K″ a ⩽ 19) and 8 lines in the v 3 band near 1361 cm −1 (4 ⩽ J″ ⩽ 61, 0 ⩽ K″ a ⩽ 17) were determined using a tunable diode laser spectrometer. In the v 1 band the broadening coefficients γ( J″, K″ a ) for the individual lines range from 0.056 to 0.086 cm −1 atm −1 for collisions with He, from 0.045 to 0.069 cm −1 atm −1 for Ne, from 0.062 to 0.092 cm −1 atm −1 for Ar, and from 0.078 to 0.12 cm −1 atm −1 for Kr. In the v 3 band they lie between 0.035 and 0.13 cm −1 atm −1 for He as the perturber, between 0.041 and 0.086 cm −1 atm −1 for Ne, between 0.05 and 0.11 cm −1 atm −1 for Ar, and between 0.076 and 0.11 cm −1 atm −1 for Kr. The broadening coefficients have an accuracy between 1.5 and 10%. We compare the determined values with former results obtained in the v 3 band of NO 2. The tendency for most of the SO 2 lines demonstrates that the Kr-broadening coefficient is larger than the Ar-broadening coefficient in contrast to NO 2.