LAUSR

In this work, we perform detailed density functional theory (DFT) calculations to systematically study the composition-dependent structural, thermodynamic and electronic properties of Mg–Al alloy clusters with 55 atoms. It is found that the Al-rich clusters, such as Mg 12 Al 43 and Mg 12 Al 43 − generally possess higher thermodynamic stability and exhibit distinctive electronic properties. Especially for Mg 12 Al 43 − , there is relatively large gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), suggesting that the Mg 12 Al 43 − may possess higher resistance to the reactivity with oxygen. In addition, we also study single O atom and 3 O 2 adsorption on the Al 55 , Mg 55 , Mg 12 Al 43 and Mg 12 Al 43 − clusters. Through comparing their adsorption energies, we find that the H1 sites (on the hollow site of one triangular facet among two edge and one vertex atoms) energetically are the most stable O adsorption site for all clusters. Most importantly, for 3 O 2 adsorbed on Mg 12 Al 43 and Mg 12 Al 43 − clusters, replacing the Al atoms of Al 55 cluster with Mg atoms can effectively weaken the adsorption of oxygen and enhance the resistance to oxidation.