Journal of Chemical Physics, Vol.104, No.10, 3598-3608, 1996
Simulation of Electron-Transfer in Polar-Solvents - Effects of Nonequilibrium Initial-State Preparation
An approximation method recently developed for computing the time evolution of electronic state populations in nonadiabatically coupled systems prepared in nonequilibrium nuclear configurations is applied to a model of a complex chemical system. A master equation formalism is used to describe an intramolecular electron transfer reaction in a polar fluid which is initiated by injection of an electron onto the donor site of the electron transfer complex. Time-dependent rate constants are obtained from molecular dynamics simulations based on electrostatic interactions between the solvent dipoles and the charge distribution on the electron transfer complex. (Appropriate Lennard-Jones potentials are also included to represent the finite size of the atoms involved.) From these rate constants electronic state populations may easily be obtained, The molecular dynamics data is also utilized in an attempt to construct an effective harmonic oscillator environment which can satisfactorily mimic the properties of the actual condensed phase medium. Some difficulties in constructing such an effective oscillator bath in cases typified by the electron injection scenario are pointed out.
Keywords:PHOTOSYNTHETIC REACTION CENTERS;SPIN-BOSON MODEL;CONDENSED PHASES;REDFIELD THEORY;CHARGE RECOMBINATION;SOLVATION DYNAMICS;TRANSFER KINETICS;FIELD MODULATION;PROTON-TRANSFER;2-STATE SYSTEM