Structure of small clusters of parahydrogen molecules

Abstract

The ground state energies and the one-body densities of parahydrogen clusters have been systematically calculated by the diffusion Monte Carlo technique in steps of one molecule from $3\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}50\phantom{\rule{0.3em}{0ex}}\text{molecules}$. These calculations show that parahydrogen clusters exhibit a clear geometrical order which excludes any liquidlike structure. A definite confirmation of the magic size for the cluster with $13\phantom{\rule{0.3em}{0ex}}\text{molecules}$ is also obtained.