Activation Energies from Transition Path Sampling Simulations

Abstract

We derive an new expression for the calculation of activation energies within the framework of transition path sampling. Using this expression one can determine activation energies without knowledge of the reaction mechanism, which is often unavailable for processes occurring in complex systems. Since in this method activation energies are calculated directly from path averages, no computationally expensive calculation of reaction rate constants is necessary. As an illustrative example, we determine the activation energy for the isomerization of a model diatomic immersed in a bath of repulsive soft particles.