VIBRATIONAL-RELAXATION IN THE B-3(1) STATE OF SO2

The vibrational relaxation rate constants of the four low-lying vibrational levels in the 3B1 state of the SO2 molecule have been investigated by a laser induced phosphorescence method in pure SO 2. The relaxation rate constants for the 3B 1(0,1,0) level have also been studied in Ar, O2, N 2, and CO2. The low-lying vibrational levels of the 3B1 state are populated from ground state SO2(X 1A1) by direct pumping, and the phosphorescence emissions from the laser excited as well as the collisional product levels are monitored. The state-to-state relaxation rate constants for the upper two levels are assigned by the kinetic simulations of the phosphorescence time profiles observed from each level. The magnitudes of the relaxation rate constants are in the range of 2.3-3.0×10-11 cm3 molecule -1 s-1 in SO2 and 0.26-1.3×10 -11 cm3 molecule-1 s-1 in other gases. © 1995 American Institute of Physics.