Greatly Enhanced Electron Affinities of Au₂ Cl Clusters (n = 1-4): Effects of Chlorine Doping

Au₂ Cl^- (n = 1-4) clusters are investigated by both laser ablation mass spectrometry and theoretical calculations. It is interesting to find that the electron affinities of neutral Au₂ Cl (n = 1-4) clusters are much larger than those of corresponding pure Au₂ clusters. Among them, the electron affinity of Au₂Cl is 4.02 eV, which can be defined as a very unique superhalogen that is quite different from classical ones of M X (M = metal, X = halogen, and n < m). Natural bond orbital and highest occupied molecular orbital analyses indicate that the extra electron is predominantly delocalized over the positively charged metal moiety in these anionic Au₂ Cl^- clusters, which is the main reason for the large electron affinities of the corresponding neutral species.