SELF-BROADENING, AIR-BROADENING, AND NITROGEN-BROADENING IN THE NU(1), BAND OF SO2

The collisional line broadening of SO2 transitions in the nu(1) band w as measured with SO2, air, and nitrogen as perturbers by applying a di ode laser spectrometer in pulse mode. Eighteen lines from the P branch (5 less than or equal to J'' less than or equal to 44, 0 less than or equal to K-a'' less than or equal to 20), eight lines from the Q bran ch (10 less than or equal to J'' less than or equal to 40, 1 less than or equal to K-a'' less than or equal to 23), and five lines from the R branch (12 less than or equal to J'' less than or equal to 35, 4 les s than or equal to K-a'' less than or equal to 8) were investigated. T he self-broadening coefficients gamma(SO2-SO2) show a significant decr ease with increasing quantum number K-a'' as expected from the theory and vary from 0.41 to 0.16 cm(-1)/atm. For small quantum numbers sever al coincidences with the theoretical predictions were found, whereas f or larger quantum numbers stronger deviations occur. In the case of co llisions with air (0.081 cm(-1)/atm less than or equal to gamma(SO2-ai r) less than or equal to 0.111 cm(-1)/atm) and nitrogen (0.095 cm(-1)/ atm less than or equal to gamma(SO2-N2) less than or equal to 0.124 cm (-1)/atm), a weaker quantum number dependence of the broadening coeffi cients could be observed, in contrast to theoretical values. (C) 1996 Academic Press, Inc.