Structural Evolution of Medium-Sized Gold Clusters Aun– (n = 36, 37, 38): Appearance of Bulk-Like Face Centered Cubic Fragment

Abstract

We report a joint experimental and theoretical study of the structural evolution of medium-sized gold clusters. We find that the most stable structures of Au36– to Au38– exhibit core–shell type structures all with a highly robust tetrahedral four-atom core. All three clusters are observed to possess two coexisting isomers in the cluster beam. The appearance of a fragment of the face centered cubic (FCC) bulk gold, that is, the pyramidal Au20–, at the size of Au38– implies that the cluster-to-bulk transformation starts to emerge at the medium size range. It is expected that larger pyramidal-like intermediates may emerge in later medium- to large-sized Au clusters beyond Au38–.