Electronic structure of small copper clusters

An all‐electron ab initio LCAO ‐ MO SCF calculation has been carried out for the electronic structure of small copper clusters (Cu n , n = 2–6). The basis set superposition error occurring in the calculation, the equilibrium configuration of Cu 3 , the bond energy in the clusters, and the localized d ‐hole in excited and ionized states of Cu 2 are closely examined.