Theoretical study of AlnV+ clusters and their interaction with Ar

Recently, it has been experimentally elucidated whether a V impurity in AlnV+ clusters occupies an external or an internal site by studying their interaction with argon as a function of cluster size [S. M. Lang, P. Claes, S. Neukermans, and E. Janssens, J. Am. Soc. Mass Spectrom. 22, 1508 (2011)]. In the work presented here we studied, by means of density functional theoretic calculations, the structural and electronic properties of AlnV+ clusters with n = 14–21 atoms, as well as the adsorption of a single Ar atom on them. For n < 17 the lowest energy structure of AlnV+ is related to that of the pure Al n+1+ cluster with the V atom substituting a surface Al atom. For n ⩾ 17 the V impurity becomes embedded in the cluster, in agreement with the experimental results, and the clusters adopt a fcc-like structure instead of the icosahedral-like skeleton of pure Al n+1+. We have studied the binding energy per atom, the second energy difference, and the V and Al atom separation energies, in comparison with those ...