Origin of the structural stability of cage-like Au144 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-144 nanoclusters, denoted as Au-144(SR)(60) and Au-144(C = CR)(60). In this study, the origin of the structural stability of golden cage Au-144 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-144 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-144 cluster is unique in size. The smaller size clusters Au-133 and Au-130 and the larger size cluster Au-279 both preferred the centre-filled golden icosahedrons, decahedrons or octahedrons.