Vibrational coherence effects on electronic curve crossing

Quantum dynamical simulations of vibrational phase coherence effects on ultrafast electronic curve crossing in condensed phases are presented for both symmetric and barrierless double well potentials. Reaction coordinate probability distributions are constructed from the reduced density matrix of the system, which provide considerable insight into the dynamics of curve crossing. The application of these ideas to retinal isomerization in rhodopsin is presented. Results suggest that coherence transfer processes are important for interpreting recent femtosecond transient absorption results on this system. (C) 1996 American Institute of Physics.