Electronic signature of the magicity and ionic bonding in Al13X (X=Li-K) clusters -: art. no. 125105

Total energies and equilibrium geometries of neutral and anionic Al-n and AlnX (n=12-14, X=Li, Na, K) clusters have been obtained following an optimization of their structure without any symmetry constraint. The calculations are based on molecular-orbital approach and the gradient-corrected density-functional theory. It is shown that although the binding energy of Al13X clusters do not differ much from that of their neighbors, their ionization potentials, highest occupied molecular orbital and lowest unoccupied molecular orbital gaps, and electron affinities bear distinct signature of their magicity. That the binding of Al-13 with alkali atoms is predominantly ionic is derived by comparing the electron affinity of Al13X with other known salts.