Melting and Equilibrium Shape of Icosahedral Gold Nanoparticles

TL;DR

This study uses molecular dynamics simulations to analyze the melting process and equilibrium shape of gold icosahedral nanoparticles, revealing surface atom mobility effects and shape evolution near melting point.

Contribution

It provides new insights into the surface atom behavior and shape changes of gold nanoparticles during melting, highlighting the role of vertex and edge atom mobility.

Findings

Surface remains ordered up to melting temperature

Vertex and edge atom mobility softens the surface structure

Cluster shape becomes nearly spherical at melting

Abstract

We use molecular dynamics simulations to study the melting of gold icosahedral clusters of a few thousand atoms. We pay particular attention to the behavior of surface atoms, and to the equilibrium shape of the cluster. We find that although the surface of the cluster remains ordered up to the melting T_m, the increasing mobility of vertex and edge atoms significantly soften the surface structure, leading to inter- and intra-layer diffusion, and shrinking of the average facet size, so that the average shape of the cluster is nearly spherical at melting.