Theoretical study of the structures and stabilities of iron clusters

Abstract

An empirical many-body potential energy function, derived previously by fitting data for two allotropes of iron (bcc and fcc), has been applied to the study of the structures and relative stabilities of iron clusters with up to 671 atoms. For small clusters, growth is predicted to occur via the fusion of tetrahedral units, leading eventually to icosahedral clusters. A subset of larger clusters, with high symmetries and shell structures (so called Geometric Shell Magic Number Clusters) was studied and the stability order icosahedral > rhombic dodecahedral (bcc) > decahedral > cuboctahedral (fcc) established in the nuclearity range studied, though crossover of stability between icosahedral and (bulk-like) bcc structures is predicted to occur at around 2000 atoms.