Global potential energy surfaces of water clusters; reaction coordinate and annealing analyses

Abstract

A global nature of the potential energy surface (PES) of water clusters, (H2O)20 and (H2O)64 was investigated by using a reaction coordinate analysis and an annealing method. It was shown for (H2O)64 that the successive reaction coordinates passing through low energy barriers lead to a deep minimum and the overall potential has so called a funnel structure, similar to PES of a protein folding. On the other hand, the smaller cluster (H2O)20 has the rugged PES of a ‘fragile’ type, resulting from distinct bond reordering.