X-ray photoelectron studies of thorium and uranium

The X-ray induced photoemission from both clean and deliberately oxidized thorium and uranium surfaces is described. The results are compared with previously reported XPS and X-ray emission measurements of electron binding energies for the heavy elements. While agreement between photoelectron and X-ray spectroscopic results is fair for most of the electron energy levels studied large discrepancies were observed in the energies of the P 1 , P 2 and P 3 levels. The authors discuss also the effect of oxidation on the spectra and on the valence bands for the metals.