Origin of the structural stability of cage-like Au clusters.

Cage-like metal nanoclusters are rarely found due to the densely packed property of metals. Recently, single crystallography has unraveled for the first time that multi-shell golden cages are formed in large-size thiolate (SR) and alkynl (CCR) protected neutral Au nanoclusters, denoted as Au(SR) and Au(CCR). In this study, the origin of the structural stability of golden cage Au clusters is studied based on the density functional theory (DFT) energy calculation and energy decomposition analysis (EDA). The formation of hollow cages rather than centre-filled icosahedrons in the Au clusters is attributed to the significant Pauli repulsion between the central gold atom and the surrounding metal shell, which leads to the decrease of the averaged formation energy of the clusters. The present study also shows that the Au cluster is unique in size. The smaller size clusters Au and Au and the larger size cluster Au both preferred the centre-filled golden icosahedrons, decahedrons or octahedrons.