Some further applications of discrete path sampling to cluster isomerization

Abstract

The discrete path sampling approach is applied to analyse the dynamics of several atomic and molecular clusters. Permutational isomerization rates are first calculated for icosahedral atomic clusters containing 13 and 55 atoms. The transformation between decahedral and icosahedral morphologies of a 75-atom cluster is then investigated, for which the potential energy surface has double funnel character. The final system considered is a cluster of twenty water molecules treated using a rigid molecule pair potential. Detailed analysis of the database of stationary points produced by the initial sampling is used to investigate the accuracy of the two-state description in each case. A clear deviation from two-state behaviour occurs for (H₂O)₂₀, where low-lying intervening minima exist.