Calculation of mean excitation energies of 3d-elements and their cations

Using response methods at the random-phase approximation level, we have calculated mean excitation energies of the 3d-elements and all their cations. We have shown that the dependence of mean excitation energies of the cations on the number of electrons is nearly the same for all 3d-elements. Using a quadratic Z-dependence of mean excitation energies in isoelectronic series, we have estimated mean excitation energies of some of the more highly charged cations of K, Ca, Ga, Ge, As, Se, Br and Kr. Also estimated values for the mean excitation energies of singly, negatively charged ions of 3d-elements are reported. We have shown how to calculate orbital mean excitation energies for the 3d-atoms from the mean excitation energy of their cations.