Global Optimisation Strategies for Nanoalloys

The computational prediction of thermodynamically stable metal cluster structures has developed into a sophisticated and successful field of research. To this end, research groups have developed, combined and improved algorithms for the location of energetically low-lying structures of unitary and alloy clusters containing several metallic species. In this chapter, we review the methods by which global optimisation is performed on metallic alloy clusters, with a focus on binary nanoalloys, over a broad range of cluster sizes. Case studies are presented, in particular for noble metal and coinage metal nanoalloys. The optimisation of chemical ordering patterns is discussed, including several novel strategies for locating low-energy permutational isomers of fixed cluster geometries. More advanced simulation scenarios, such as ligand-passivated, and surface-deposited clusters have been developed in recent years, in order to bridge the gap between isolated, bare clusters, and the situation observed under experimental conditions. We summarise these developments and consider the developments necessary to improve binary cluster global optimisation in the near future.