Transition State Theory for solvated reactions beyond recrossing-free dividing surfaces

TL;DR

This paper develops a new approach to calculating reaction rates in solvated systems, extending transition state theory to non-Markovian friction and invariant manifold methods, demonstrated on a LiNC/LiCN isomerization model.

Contribution

It introduces a novel method for defining optimal dividing surfaces in non-Markovian systems and derives an explicit rate expression using invariant manifolds, bypassing traditional dividing surface issues.

Findings

Optimal dividing surfaces can be defined in non-Markovian systems.

Invariant manifold approach yields explicit rate expressions.

Method accurately predicts LiNC/LiCN isomerization rates.

Abstract

The accuracy of rate constants calculated using transition state theory depends crucially on the correct identification of a recrossing--free dividing surface. We show here that it is possible to define such optimal dividing surface in systems with non--Markovian friction. However, a more direct approach to rate calculation is based on invariant manifolds and avoids the use of a dividing surface altogether, Using that method we obtain an explicit expression for the rate of crossing an anharmonic potential barrier. The excellent performance of our method is illustrated with an application to a realistic model for LiNC$\rightleftharpoons$LiCN isomerization.