Structure and stability of neutral Al-Mg nanoclusters up to 55 atoms

The geometries of aluminum-magnesium nanoalloys are explored using a genetic algorithm applied to the Gupta potential function and tuned to search for the 10 lowest energy minima for each cluster size and composition. Each structure is re-optimized using density functional theory calculations, allowing both a classical and quantum analysis of the system. Average binding energies, excess energies and HOMO-LUMO gaps are calculated. Differences between classical and quantum descriptions are discussed. The results reveal structures that are particularly stable, and a discussion on magic numbers of valence electrons is presented.