NOBLE-GAS PRESSURE BROADENING IN THE NU(1)-BAND AND NU(3)-BAND OF SO2STUDIED WITH IR TUNABLE DIODE-LASER SPECTROSCOPY

Detailed investigations of the pressure broadening of SO2 for collisio ns with the noble gases He, Ne, Ar and Kr are presented. The broadenin g coefficients of 14 lines in the nu(1) band near 1151 cm(-1) (13 less than or equal to J'' less than or equal to 44, 3 less than or equal t o K-a'' less than or equal to 19) and 8 lines in the nu(3) band near 1 361 cm(-1) (4 less than or equal to J'' less than or equal to 61, 0 le ss than or equal to K-a'' less than or equal to 17) were determined us ing a tunable diode laser spectrometer. In the nu(1) band the broadeni ng coefficients gamma (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 nu(3) band they lie between 0.035 and 0.13 cm(-1) atm(-1) for He as the perturber, bet ween 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. T he broadening coefficients have an accuracy between 1.5 and 10%. We co mpare the determined values with former results obtained in the nu(3) band of NO2. The tendency for most of the SO2 lines demonstrates that the Kr-broadening coefficient is larger than the Ar-broadening coeffic ient in contrast to NO2.