Size-Dependent Structural Evolution and Chemical Reactivity of Gold Clusters

Ground-state structures and other experimentally relevant isomers of Au15 - to A u24 - clusters are determined through joint first-principles density functional theory and photoelectron spectroscopy measurements. Subsequent calculations of m olecular O2 adsorption to the optimal cluster structures reveal a size-dependent reactivity pattern that agrees well with earlier experiments. A detailed analys is of the underlying electronic structure shows that the chemical reactivity of the gold cluster anions can be elucidated in terms of a partial-jellium picture, where delocalized electrons occupying electronic shells move over the ionic ske leton, whose geometric structureis strongly influenced by the directional bondin g associated with the highly localized d-band electrons.