High-energy spectroscopic study of the occupied and unoccupied5fand valence states in Th and U metals

X-ray photoemission spectroscopy and bremsstrahlung isochromat spectroscopy have been used to investigate the electronic density of states of metallic Th and U, below as well as above the Fermi level. In contrast to the discrete $4f$ levels observed in the rare earths, the $5f$ states in these metals are found to be delocalized and to form relatively narrow bands. The experimental spectra are compared to recent calculations of the density of states.