SULPHUR DIOXIDE EXCITED STATES

$^{1}$ C. A. Langhoff and G. W. Robinson, Chem. Phys. 6, 34 (1974). $^{2}$ J. O. Berg, Chem. Phys. Lett. 41, 547 (1976).Author Institution: Monash University; Department of Chemistry, Texas Tech University; Department of Chemistry, University of CaliforniaThe first excited singlet state absorption system of $SO_{2}$ is interpreted as arising predominantly from massive vibronic coupling between a zero order, narrow, Franck-Condon allowed $^{1}$B$_{1}$ state and the vibronic levels of a forbidden $^{1}$A$_{2}$ state. Calculations based on the Langhoff-Robinson-$Berg^{1,2}$ model using reasonable assumptions about the nature and number of the $A_{2}$ vibronic states shows the interaction matrix element averages out at roughly 900 $cm^{-1}$ for each significantly interacting state. Single vibronic fluorescence spectra are shown to support the application of this model to $SO_{2}$