Observation of Itinerant5fStates in Thorium Metal

Abstract

Normal-incidence reflectivity measurements between 0.5 and 6 eV on thorium metal reveal the existence of bandlike (or itinerant) $f$ states several electron volts above the Fermi energy. The predictions of relativistic band-structure determinations are in qualitative agreement with experiment. This study provides the first direct observation and characterization of $5f$ electrons in metals as being itinerant in nature and unlike the $4f$ states in the rare earths.