Non-adiabatic and intersystem crossing dynamics in SO2. II. The role of triplet states in the bound state dynamics studied by surface-hopping simulations

The importance of triplet states in the photorelaxation dynamics of SO2 is studied by mixed quantum-classical dynamics simulations. Using the SHARC method, standing for Surface Hopping including ARbitrary Couplings, intersystem crossing (ISC) processes caused by spin-orbit coupling are found occurring on an ultrafast time scale (few 100 fs) and thus competing with internal conversion. While in the singlet-only dynamics only oscillatory population transfer between the B-1(1) and (1)A(2) states is observed, in the dynamics including singlet and triplet states we find additionally continuous ISC to the B-3(2) state and to a smaller extent to the B-3(1)/(3)A(2) coupled states. The populations obtained from the dynamics are discussed with respect to the overall nuclear motion and in the light of recent TR-PEPICO studies [I. Wilkinson, A. E. Boguslavskiy, J. Mikosch, D. M. Villeneuve, H.-J. Worner, M. Spanner, S. Patchkovskii, and A. Stolow, Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy, J. Chem. Phys. 140, 204301 (2014)]. (C) 2014 AIP Publishing LLC.