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

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.

12 pages, 5 figures, 1 table, one additional figure with extended discussion in the text, extended list of references

References in corpus (7)

• Thermodynamics and equilibrium structure of Ne_38 cluster: Quantum Mechanics versus Classical
• Heat capacity estimators for random series path-integral methods by finite-difference schemes
• Gaussian resolutions for equilibrium density matrices
• Metropolis Methods for Quantum Monte Carlo Simulations
• Imaginary time Gaussian dynamics of the Ar_3 cluster
• A fast Variational Gaussian Wave-packet method: Size-induced structural transitions in large neon clusters
• First-order corrections to semiclassical Gaussian partition functions for clusters of atoms