The Effect of Vibrationally Excited Levels on the Pressure Saturation of the Collisional Quenching of the <TEX>$^3B_1;State;of;SO_2</TEX>

The pressure saturation effect on the phosphorescence decay rates of the <TEX>$^3B_1$</TEX> State of <TEX>$SO_2$</TEX> has been reinvestigated by the laser induced phosphorescence method in pure <TEX>$SO_2$</TEX>. We have attempted to fit the pressure dependence of the phosphorescence decay rates using the radiationless transition model by introducing different coupling constants for each vibrational level ofthe 3B1 state. The experimental decay rates can be fitted well, when the coupling constants for the (0,0,0), (0,1,0) and (0,2,0) levels of the <TEX>$^3B_1$</TEX> state are <TEX>$7.2;{ imes};10^{-4}$</TEX>, <TEX>$2.2;{ imes};10^{-3}$</TEX> and <TEX>$5.9;{ imes};10^{-3};cm^{-1}$</TEX>, respectively.