String Method for the Study of Rare Events

TL;DR

The paper introduces a novel string method for efficiently computing transition pathways, free energy barriers, and rates in complex systems, demonstrated on molecular and magnetic systems.

Contribution

It proposes a new string-based approach to identify transition paths and calculate barriers, improving efficiency over existing methods.

Findings

Successfully applied to Lennard-Jones clusters.

Accurately computed transition rates in magnetic films.

Demonstrated efficiency and accuracy of the method.

Abstract

We present a new and efficient method for computing the transition pathways, free energy barriers, and transition rates in complex systems with relatively smooth energy landscapes. The method proceeds by evolving strings, i.e. smooth curves with intrinsic parametrization whose dynamics takes them to the most probable transition path between two metastable regions in the configuration space. Free energy barriers and transition rates can then be determined by standard umbrella sampling technique around the string. Applications to Lennard-Jones cluster rearrangement and thermally induced switching of a magnetic film are presented.