Systematic Study of Au6 to Au12 Gold Clusters on MgO(100) F Centers Using Density-Functional Theory

We present an optimized genetic algorithm used in conjunction with density-functional theory in the search for stable gold clusters and O-2 adsorption ensembles in F centers at MgO(100). For Au-8 the method recovers known structures and identifies several more stable ones. When O-2 adsorption is investigated, the genetic algorithm is used to imitate structural fluxionality, increasing the O-2 bond strength by up to 1 eV. Extending the method to Au-6,Au-10,Au-12, strong O-2 adsorption configurations are found for all sizes. However, the effect of fluxionality appears to wear off with increasing cluster size.