A variational Monte Carlo study of argon, neon, and helium clusters

Clusters of rare gas atoms provide an interesting setting for the study of the issue of quantum mechanical localization. The properties of these clusters of 2–7 atoms are calculated using variational Monte Carlo methods. To our knowledge, this is the first variational Monte Carlo study of localized clusters and new solidlike wave function forms, including shadow, multiple bond length, and Boltzmann-like wave functions, are reported. Diffusion Monte Carlo methods provide an independent, exact value of the ground state energy, useful as a check of the variational results. The properties of the variational wave functions, when analyzed in terms of probability distribution functions, quench studies, and visual examination of the wave functions, indicate delocalized helium and localized argon and neon clusters.