Relativistic, relaxation, and correlation effects in spectra of Cu II

The influence of relativistic, relaxation, and correlation effects on the low-lying energy levels of the 3d¹⁰,3d⁹4s, and 3d⁹4p configurations of Cu II have been investigated. Large-scale multiconfiguration Dirac-Fock wave functions were applied to calculate the excitation energies and the electric-dipole-allowed transition probabilities and to allow for a systematic improvement of the computations. From these calculations, the theoretical lifetimes of the 3d⁹4p levels are derived and compared with previous experiments and computations. Our results show that we provide not only an improved data basis for the low-lying levels of Cu II but also a useful computational model for studying other ions along the nickel isoelectronic sequence.