Super-atom properties of 13 atom clusters of group 13 elements

We report first principles calculations of the geometry and

electronic structure of 13 atom clusters of boron, aluminium,

gallium and indium. These density functional theory calculations

support the jellium model in the energy levels and

molecular orbitals of the cluster and enable us to discuss the

relevance of the superatom concept. We go on to examine a

number of cluster symmetries in detail as a function of charge

and comment on the successes and limitations of the jellium and

superatom models in describing these clusters. In particular we

find that the monovalent anionic cluster is the most stable and

has the most symmetric structure. As charge changes the

symmetry of the clusters decreases in a way that is dependent on

symmetry and charge, but not atomic species.