Nonadiabatic effects in the photodissociation of H2S

The photodissociation of H2 S in the first absorption band is studied by time-dependent wave packets evolving in two electronic states; the lower state is dissociative and the upper one is bound. The adiabatic potential energy surfaces and transition dipole functions are constructed from ab initio calculations while the nonadiabatic coupling is adjusted. The diffuse structure superimposed on the broad absorption spectrum is due to symmetric stretch motion in the upper (bound) electronic state which is strongly quenched by nonadiabatic coupling. This is different from the photodissociation of water in the first band.