Probing structural and electronic properties of divalent metal Mg n+1 and SrMg n (n=2-12) clusters and their anions

Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size, shape, and doping. In this work, the combination of the CALYPSO code and density functional theory (DFT) optimization is employed to explore the structural properties of neutral and anionic Mg n + 1 and SrMg n (n = 2-12) clusters. The results exhibit that as the atomic number of Mg increases, Sr atoms are more likely to replace Mg atoms located in the skeleton convex cap. By analyzing the binding energy, second-order energy difference and the charge transfer, it can be found the SrMg9 cluster with tower framework presents outstanding stability in a studied size range. Further, bonding characteristic analysis reveals that the stability of SrMg9 can be improved due to the strong s-p interaction among the atomic orbitals of Sr and Mg atoms.