DFT study of electronic structure and geometry of anionic copper clusters Cu_n^- (n = 11, 12, 13)

Based on both total energy calculations and comparison of experimental and calculated characteristics of photoelectron spectra (PHES), the structural assignment of Cu₁₁^-, Cu₁₂^- and Cu₁₃^- clusters has been made using DFT model with previously developed S2LYP functional. In case of Cu₁₃^- cluster our decisions were also based on similarity of the geometries of copper and sodium clusters. The calculated characteristics of PHES for all the assigned structures are in excellent agreement with the experimental ones. The assigned geometries of Cu₁₁^- and Cu₁₂^- have been compared with those of recently established structures of silver clusters, which turned out to be very similar. In the meantime, the structure of the most stable Cu₁₃^- cluster is significantly distorted in comparison with the structure of Na₁₃^- cluster.