Size-dependent structural and electronic properties ofTin clusters(n≤100)

Abstract

The results of a genetic-algorithms search for structures of titanium clusters with up to 100atoms are presented. An empirical pair potential has been used in describingthe interatomic interactions during the genetic-algorithms search. The resultingglobal-minimum structures have been used as starting geometries of geometryoptimizations using a density-functional tight-binding method. Structural, energetic, andelectronic properties are analysed and compared. Special attention is paid to the sizedependence of the properties, including point groups, radial atomic distributions,bond lengths, moments of inertia, stability, Mulliken populations and frontierorbitals. Similarity functions are defined to facilitate the analysis of the growth ofthe clusters. It turned out that the empirical potential favours highly symmetricgeometries, that exhibit small distortions upon relaxation using the electronic-structuremethod. Some larger, particularly stable clusters are fragments of the hcp bulkstructure but an overall transition to bulk structure cannot be seen below 100 atoms.