Structural information about the $\text{Ar}_6$ cluster with the frozen Gaussian imaginary time propagator

TL;DR

This paper introduces an efficient semiclassical method to analyze the structural properties and dissociation behavior of the Ar6 cluster at low temperatures, capturing subtle thermal effects and isomer formations.

Contribution

The authors extend the frozen Gaussian imaginary time propagator to include inter-atomic distances and variances, enabling detailed structural analysis with reduced computational effort.

Findings

The Ar6 cluster dissociates almost in one step at higher temperatures.

A second isomer appears as a precursor to dissociation.

The method detects small temperature differences affecting cluster structure.

Abstract

A numerically cheap way to obtain structural information about clusters of rare gas atoms at low temperatures is developed. The semiclassical frozen Gaussian imaginary time propagator is extended such that it can account for the mean values of all inter-atomic distances in the cluster and their variances. To reduce the required numerical effort an approximation for the mean values is developed which preserves the quality of the results offered by the semiclassical ansatz. The method is applied to the $\text{Ar}_6$ cluster. It is found that the cluster dissociates almost in one step to six free atoms when the temperature is increased. Precursors of the dissociation are only observable in the distances of the atoms via the appearance of a second isomer. The process is almost classical. However, the method is able to resolve small differences in the temperatures at which the dissociation takes place and in the mean distances of the bound configuration.