Photoemission studies of f states and valence bands in several rare-earth and uranium compounds

Photoemission spectroscopy measurements of f states and valence band energies are reported for EuS, GdS, and US using photon energies for 5 to 41 eV. The energy dependence of photoemission spectra permits the "l" character of various levels to be identified. Characteristic energy-dependent emission strengths of "p", "d", and "f" states are observed. In a typical case, the emission strength of the 4f7 level in EuS increases about 100-fold relative to the ∼2.9-eV-wide valence "p" band (which lies just below the 4f7 level) as ℏω increases from 10 to 41 eV. Metallic GdS shows a "d"-like conduction band at the Fermi level EF, a 4.5-eV-wide "p"-band centered at ∼5 eV below EF, and a 4f7 level at 9 eV below EF. Uranium monosulphide shows a narrow "f-d" conduction band at EF and a 4.7-eV-wide "p"-band centered at 4.7 eV below EF. © 1971 The American Institute of Physics.