Hard X-Ray Photoelectron Spectroscopic Analysis of single crystal UPd$_{3}$, UGe$_{2}$, and USb$_{2}$

Hard X-ray Photoelectron Spectroscopy (HAXPES) with 7.6 keV photons has been performed on single crystals of UPd3, UGe2, and USb2 at the European Synchrotron Radiation Facility (ESRF). A potential correlation between the localization/itinerancy of the 5f electrons and the core levels of these materials is investigated. The greatly reduced surface sensitivity of HAXPES enabled observation of the bulk core levels in spite of some surface oxidation. An 800 meV splitting of the Sb 3d and 4d core levels was observed. The splitting of the Sb core levels is attributed to manifestations of two distinct binding modes within the USb2 single crystal as supported by consideration of interatomic distances and charge transfer calculations.