MELTING OF THE GLASS-LIKE 19-ATOM GOLD CLUSTER

Abstract

In this paper, the melting behaviors of the glass-like cluster Au 19 are calculated and analyzed by using standard microcanonical molecular-dynamics simulations. The calculated results show a multi-step melting process. The first stage involves the majority of the surface atoms (14 atoms). An interesting phenomenon is that the minority of the surface atoms (4 atoms) are still in a solid-like state. The second stage involves all of the surface atoms. But there are two sites where the atoms stay for a relatively long time. The third stage corresponds to the frequent isomerizations involving all the surface atoms. The final stage consists of isomerization transitions involving all of the atoms, including the central atom of the cluster. The unique melting processes lead to the unique features of the caloric curve, the root-mean-square bond-length fluctuation, and the heat capacity of the glass-like Au 19.