Resonant-inverse photoemission study of Pr compounds in 4d-4f excitation region

We have measured the resonant-inverse photoemission spectra for PrSn3, PrCo2, and PrAg in the Pr 4d-4f excitation region. Similar to the case of Ce compounds, the spectra strongly depend on the energy of the incident electron. We determined the "on-resonance" and "off-resonance" energies as 124 and 115 eV, respectively, and these energies are common to all the Pr compounds. The dependence of the spectra on the energy of the incident electron is well explained by the calculation based on the single-impurity Anderson model considering the bulk and surface components. A clear shoulder near the Fermi energy was observed in the on-resonance spectra for PrSn3 and PrCo2, and this shoulder is assigned to the f(2) final-state peak. The result of the analysis shows that the Pr 4f electron in PrSn3 and PrCo2 has more itinerant charactaristics compared with that in PrAg, which is consistent with the result of the photoemission spectroscopy experiments.