A diffusion Monte Carlo study of small para-Hydrogen clusters

TL;DR

This paper uses diffusion Monte Carlo to calculate ground state energies and chemical potentials of small para-Hydrogen clusters, improving previous methods and comparing results with other Monte Carlo techniques.

Contribution

It introduces enhanced diffusion Monte Carlo calculations including three-body correlations and improved error estimation for pH2 clusters.

Findings

No additional magic clusters predicted besides 13 molecules.

Results differ from path integral Monte Carlo predictions.

Method improvements lead to more accurate energy calculations.

Abstract

Ground state energies and chemical potentials of parahydrogen clusters are calculated from 3 to 40 molecules using the diffusion Monte Carlo technique with two different pH2-pH2 interactions. This calculation improves a previous one by the inclusion of three-body correlations in the importance sampling, by the time step adjustement and by a better estimation of the statistical errors. Apart from the cluster with 13 molecules, no other magic clusters are predicted, in contrast with path integral Monte Carlo results.