MODEL APPROACH TO NONADIABATIC REACTION PROCESSES

A transport theory of reactive flux is developed on the basis of a model potential-energy surface with an unbranched reaction path and many harmonic vibrations perpendicular to this path. Coriolis forces are ignored and the vibrational spectrum is assumed to be slowly varying with the reaction coordinate f. An interaction between translational and vibrational motion on the potential-energy surface, similar to the one in the Fröhlich Hamiltonian, is derived. The method of equations of motion is employed to calculate Green's functions. With the assumption of equilibrium for the bound degrees of freedom, Green's functions containing higher correlations can be expressed exactly in terms of Green's functions of lower order. Solutions of the integral equations are given for physically relevant energy regions. Explicit account is taken of the internal linewidth and the effects of reactive resonance scattering. The results are expressed in terms of equilibrium ensemble averages and reaction rates.