Abstract: Equilibrium geometries, stabilities, preferred fragmentation channels, CO adsorption features and spectroscopic properties of Cu_n^- and Cu_nCO^- were investigated by the density functional theory(DFT) combined with the relativistic effective core potentials. The calculated results show that the odd numbered copper cluster generally has a relatively higher ionization potential than the even numbered species, and CO dissociation from the odd Cu₅CO^- requires the largest energy of 1.21 eV among such copper cluster monocarbonyls here. Such high stabilities of the odd copper cluster anions and Cu₅CO^- are consistent with the closed shell effect within the jellium shell model approximation. B3LYP fragmentation energies reveal that the preferred dissociation channel of the odd numbered copper cluster anion is the loss of copper dimer Cu₂, while the loss of Cu is favored in energy for the even numbered copper cluster anion. On the basis of current DFT calculations, the size dependences of static polarizabilities and the features of CO adsorption on copper clusters were discussed.

Key words: Cu_n^- and Cu_nCO^-(n=2-7) cluster, DFT/B3LYP, Stabilities, Mean static polarizabilities