Among coinage metal nanoclusters with 55 atoms, only Ag 55 - and Cu 55 - are the geometric magic-number clusters, as both exhibit icosahedral symmetry. Au 55 - , however, exhibits much lower symmetry due largely to the strong relativistic bonding effect. In this study, we collect a much larger population (>10,000 isomers) of low-energy isomers of Au 55 - to Au 60 - by using the combined density-functional theory and basin-hopping global optimization method. We also include the spin-orbit effect in the density-functional theory computation to achieve simulated photoelectron spectra in quantitative fashion. Remarkably, we uncover that the Au 13 core with the highest icosahedral (I h ) symmetry emerges at the size of Au 60 - . Stability analysis suggests that Au 57 - with 58 valence electrons, an electronic magic number, is the relatively more stable cluster in the size range considered. Overall, in this size range we reveal a compromise between the trend toward having a perfect icosahedral 13-atom core and the strong relativistic bonding effect.
ASJC Scopus subject areas
- Materials Science(all)
- Physical and Theoretical Chemistry