Rate constants for diffusive processes by partial path sampling

TL;DR

This paper presents a new path sampling method for calculating rate constants in highly diffusive systems, improving efficiency by focusing on partial trajectories and assuming memory loss along the reaction coordinate.

Contribution

The paper introduces a partial path sampling algorithm based on transition interface sampling that enhances efficiency for diffusive processes by sampling only relevant trajectory segments.

Findings

The new method scales linearly with barrier length, unlike previous quadratic scaling.

Comparison shows improved computational efficiency over traditional TIS.

Memory loss assumption is validated for diffusive systems.

Abstract

We introduce a path sampling method for the computation of rate constants for systems with a highly diffusive character. Based on the recently developed algorithm of transition interface sampling (TIS) this procedure increases the efficiency by sampling only parts of complete transition trajectories confined within a certain region. The algorithm assumes the loss of memory for highly diffusive progression along the reaction coordinate. We compare the new technique to the TIS method for a simple diatomic system and show that the computation time of the new method scales linearly, instead of quadraticaly, with the length of the diffusive barrier. The validity of the memory loss assumption is also discussed.