THEORETICAL-STUDY OF THE STRUCTURES AND STABILITIES OF IRON CLUSTERS

An empirical many-body potential energy function, derived previously b y fitting data for two allotropes of iron (bcc and fee), has been appl ied to the study of the structures and relative stabilities of iron cl usters with up to 671 atoms. For small clusters, growth is predicted t o occur via the fusion of tetrahedral units, leading eventually to ico sahedral clusters. A subset of larger clusters, with high symmetries a nd 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 nuclearit y range studied, though crossover of stability between icosahedral and (bulk-like) bcc structures is predicted to occur at around 2000 atoms .