A study of electronic and bonding properties of Sn doped Li_n clusters and aluminum based binary clusters through electron localization function

Abstract

We have carried out a thorough investigation of bonding and energetics in two different class of heteroatomic clusters viz. single impurity based Li_nSn (n ≤ 9) clusters and mixed aluminum-based binary clusters Al₄X₄ (X=Be, Mg, B, Si). We employ first principle Born-Oppenheimer molecular dynamics within the framework of density functional theory using generalized gradient approximation. The bonding characteristics have been analyzed using electron localization function (ELF) along with charge density and valence molecular orbital pictures. The analysis of bonding through ELF reveals that in Li_nSn (n ≤ 9) clusters there is a transition from ionic bond to a metallic bond through an intermediate ionic-metallic bond. On the other hand, it is found that Al₄X₄ (X=Be, Mg, B, Si) clusters show interesting characteristics of lone pairs on Al, polar covalent bonding, and a multicenter bonding. We demonstrate that ELF can play an important role in analyzing different types of bonding characteristics in heteroatomic clusters.