Saddle point model for atom transfer reactions in solution

Abstract

A simple classical model for a collinear atom transfer (exchange) reaction in solution is investigated. The reaction is analyzed in terms of reactive and nonreactive modes in a saddle point region. Dynamical solvent effects are treated at the generalized Langevin equation level. The reaction rate constant k is determined and compared to the transition state theory prediction k^TST. It is found that, for typical reactions governed by sharp potential barriers, the solvent is not very effective in the saddle region in reducing k much below k^TST. In addition, solvent‐induced coupling of the reactive mode to nonreactive modes of motion typically has only a small influence on k. Some limitations of the model are discussed.