Excitation effects on the quantum dynamics of two-dimensional photoinduced nonadiabatic processes

Results are presented from quantum dynamical simulations of vibrationally coherent condensed phase electronic surface crossing processes that take into account the relative positions of the ground, reactant, and product excited states. We find that the degree of Franck-Condon activity in the various vibrational modes can have a significant effect on the surface crossing probability, the nature and magnititude of coherent surface recrossings, and the nature of vibrational motion in the product state when motion in the reactant well is underdamped. The results are discussed in the context of recent femtosecond studies of the photodissociation of the myoglobin-nitric oxide complex and the photoisomerization of the retinal prosthetic group in the rhodopsin system.