Abstract
The relativistic local-spin-density approximation and the relativistic generalized gradient approximation (RGGA) are employed to calculate interconfiguration energies including 4s-3d transition energies, 4s ionization energies, and 3d ionization energies for the first transition-metal atoms. For 3d ionizations, the RGGA, which includes relativistic corrections as well as gradient effects, yields the best results. For 4s-3d transitions, the relativistic effects also systematically improve the accuracies of the results. However the 4s removal energies from the relativistic schemes are slightly too large, whereas the self-interaction-correction local-spin-density approximation, which provides correct long-range effective potentials, gives accurate results.