StudiesontheStabilityofOn-topAl13I_nm（n=1～12,m=–1,0,+1）Clusters

Energetic and electronic structures of the on-top Al13Inm (n = 1～12, m = –1, 0, +1) clusters have been investigated by employing a first-principles pseudo-potential plane wave method. Several parameters such as binding energies, second differences of energy and vertical-electron detachment energies have been adopted to characterize and evaluate the structure stability of Al13In-(n = 1～12) clusters. The optimized models show that the Al13 moieties in the clusters can not retain the original regular icosahedron structure. Results from binding energy and second difference of energy show that Al13In and Al13In-clusters with even n are more stable than those with odd n in contrast with Al13In+ clusters. The calculation of vertical-electron detachment energies (VDE) of Al13In clusters indicates that Al13In and Al13In-clusters with even n are closer to the closed shell of the Jellium model. Further analysis of electron density of states and electron density differences reveals that the enhanced stability of Al13In-clusters is not only associated with the closed shell of valence electrons but also with the bonding type between I and associated Al atoms.