Electronic excitations in the transition metals V, Zr, Nb, Mo, and Ta

The np core-loss spectra and the associated deexcitation processes for the transition metals V (n=3), Zr, Nb, Mo (n=4), and Ta (n=5) have been studied in low-energy electron scattering experiments in order to investigate the dependence of their nature on the principle quantum number n. For the metals with n=3 and n=4, the measurements are accounted for in terms of atomic transitions involving the excitation and the decay of localized d electrons. The observations on V can qualitatively be compared with published computations for isolated atoms. While the 5p core excitations for Ta resemble the gross features of the unoccupied d-band density of states, the decay processes involve, besides the conventional $O_2$VV and $O_3$VV Auger transitions, autoionization emission related to 5${\mathit{p}}^6$5${\mathit{d}}^{\mathit{N}}$-5${\mathit{p}}^5$5${\mathit{d}}^{\mathit{N}+1\mathrm{}}$-5${\mathit{p}}^6$5${\mathit{d}}^{\mathit{N}\mathrm{-}1}$+εf transitions.