Theoretical studies of the energetics and structures of atomic clusters

J Xie,J D Doll,David L Freeman,J A Northby

doi:10.1063/1.457447

Abstract

Comparative calculations of the binding energy and structure of relaxed closed-shell clusters of icosahedral and cuboctahedral point group symmetry are reported. The atoms are presumed to interact via either the Lennard-Jones or the Aziz–Chen (HFD–C) pair potential. The IC structure is found to be lower in total energy for less than 14 shells (10 179 atoms) in the Lennard-Jones case and for less than 13 shells (8217 atoms) in the HFD–C case. Detailed energetics are analyzed in order to elucidate the mechanism for the transition from icosahedral to cuboctahedral symmetry.

Highlights

The IC structure is found to be lower in total energy for less than 14 shells (10 179 atoms) in the Lennard-Jones case and for less than 13 shells (8217 atoms) in the HFD-C case
Detailed energetics are analyzed in order to elucidate the mechanism for the transition from icosahedral to cuboctahedral symmetry
One of the more interesting theoretical questions in the study of clusters is the properties of the minimal energy structures of finite systems interacting via short-range isotropic pair potentials

Summary

Introduction

One of the more interesting theoretical questions in the study of clusters is the properties of the minimal energy structures of finite systems interacting via short-range isotropic pair potentials. This question is motivated by the related experimental issue ofthe structure offree rare gas clusters. Small clusters are believed to be characterized by an icosahedrally derived noncrystalline symmetry. IOn the other hand, it is known that bulk rare gas crystals have a face centered cubic (FCC) crystalline symmetry.[2]. It is natural to ask at what cluster size the FCC structure becomes lower in energy than the icosahedral (lC) structure. It is of interest to determine the mechanisms that induce the transition from one to the other as the size of the system increases

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