Absorption and resonance emission spectra of SO2((X)over-tilde(1)A(1)/(C)over-tilde(1)B(2)) calculated from ab initio potential energy and transitiondipole moment surfaces

We report here an analytical fit of the transition dipole moments between ( X) over tilde (1)A(1) and (C) over tilde B-1(2) electronic states of SO2 ca lculated using a high level ab initio method. The absorption spectrum as we ll as the resonance emission spectra from several low-lying (C) over tilde B-1(2) vibrational levels are calculated using a newly developed ab initio potential energy surface (PES) and the transition dipole functions. The cal culated spectra are in semi-quantitative agreement with available experimen tal data. A strong non-Condon effect is found for the emission spectra. (C) 2000 Elsevier Science B.V. All rights reserved.