Correlation function approach to radiationless transitions

Abstract

The rate constant for radiationless transitions is expressed in terms of a correlation function similar to the Kubo formulas for transport coefficients. A strong coupling theory for the interaction of the electron with the molecular vibrations is adopted to analyze the time dependent correlation function. For a large molecular system, rapid convergence of this function is found due to strong interference effects. This fact is taken into account by applying the saddle point method for the time integration. The results directly show the dependence of the rate constant upon the energy difference between the relevant electronic states as well as the dependence upon the displacement and distortions of the adiabatic potentials.