A combined quantum-classical dynamics method for calculating thermal rate constants of chemical reactions in solution

We present a combined quantum-classical-stochastic dynamics method based on the flux–flux correlation function for calculating the thermal rate constants of chemical reactions in solution or in biological systems. The present method is an extension of an earlier method by Metiu and co-workers [J. Chem. Phys. 88, 2478 (1988)] to include stochastic dynamics. The method is tested by applying it to a simple model of hydrogen atom transfer reaction in solution. We also examine the behavior of the flux–flux correlation function and the rate constants as functions of viscosity.