Nature of the5felectrons in uranium nitride: A photoelectron spectroscopic study of UN, U, UO2, ThN, and Th

Abstract

Ultraviolet and x-ray-photoelectron spectra of core and valence levels in U metal, UN, U${\mathrm{O}}_2$, Th, and ThN have been obtained. These spectra demonstrate the existence in uranium nitride of a sharp band of $f$ states (containing 2.2±0.5 electrons) at the Fermi level. The anomalously broad $4f$ core levels in UN are discussed in terms of several possible energy-loss mechanisms, including configuration interaction and alternating valency. No change is seen in the density of $f$ states of UN on cooling through the antiferromagnetic transition.