Structures and Stabilities of Alkaline Earth Metal Oxide Nanoclusters: A DFT Study

Abstract

The stability orders of a number of alkaline earth oxide cluster isomers (MO)n, M = Mg, Ca, Sr, Ba and 1≤n≥6 have been determined by means of density functional theory studies using the LDA-PWC functional. Among the candidate structures, the hexagonal-ring-based isomers and the slab shapes are found to display similar stabilities. Stacks of hexagonal (MO)3 rings are found to be the slightly preferred growth strategy among the (MgO)6, isomers. In contrast, the slab structures are slightly preferred for the other alkaline metal oxide (MO)6 clusters. An explanation based on packing and aromaticity arguments has been proposed. This study may have important implications for modeling and understanding the initial growth patterns of small nanostructures of alkaline earth metals.