Dissipative wave-packet dynamics and electron transfer

Coherent wave-packet dynamics on coupled electronic surfaces within a conde nsed-phase environment is studied. Based on a path integral approach, exact expressions for the case of a one-dimensional reaction coordinate in a don or-acceptor complex are derived. The path integrals over the electronic deg ree of freedom are further evaluated by applying the golden rule approximat ion. This procedure allows for an exact treatment of the coupling between s olvent or residual molecular degrees of freedom and the reaction coordinate . A detailed picture of the intimate relation between dissipative wave-pack et motion and electron transfer is gained also for lower temperatures, stro ng coupling and slow bath modes, where Redfield type of equations cannot be used. The electron transfer triggered by the coherent vibronic motion lead s to a stepwise decay of the population in the donor state. On the acceptor surface the wave-packet dynamics displays a complex interference pattern. Further, it turns out that for a reaction coordinate fast compared to the e nvironmental modes the electronic population dynamics is very sensitive to the initial correlations between bath and reactive mode. (C) 2001 American Institute of Physics.