Theoretical investigation of the low-lying electronic states of Cu, Zn, and their ions

The ab initio SCF-CI procedure is utilized to calculate the energies of the low-energy excitation and ionization processes in Cu and Zn, as well as the electron affinity of Cu. Although tight f functions are required for describing d2 → f2 contributions to the correlation energy of individual states, diffuse f functions are found to be generally more important for describing the differential correlation in the electronic excitation and ionization processes.