Energy landscape, two-level systems and entropy barriers in Lennard-Jones clusters

TL;DR

This paper introduces an efficient algorithm to identify saddle points in Lennard-Jones clusters, enabling the study of minima, two-level systems, and entropy barriers, with implications for understanding cluster energy landscapes.

Contribution

It presents a novel numerical method for locating saddle points and analyzing two-level systems in Lennard-Jones clusters of up to 80 atoms.

Findings

Identified thousands of minima and saddle points in clusters.

Located pairs of minima forming two-level systems.

Evaluated entropic contributions to energy barriers.

Abstract

We develop an efficient numerical algorithm for the identification of a large number of saddle points of the potential energy function of Lennard- Jones clusters. Knowledge of the saddle points allows us to find many thousand adjacent minima of clusters containing up to 80 argon atoms and to locate many pairs of minima with the right characteristics to form two-level systems (TLS). The true TLS are singled out by calculating the ground-state tunneling splitting. The entropic contribution to all barriers is evaluated and discussed.