PHOTOEMISSION AND BREMSSTRAHLUNG ISOCHROMAT SPECTRA OF U3P4 AND U3AS4

The electronic structures of U3P4 and U3As4 single crystals are probed by x-ray and vacuum ultraviolet photoemission spectroscopy (XPS and UPS) as well as by x-ray bremsstrahlung isochromat spectroscopy (BIS). The BIS spectra show a broad peak at similar to 1.8 eV above the Fermi level (E(F)) with a noticeable tail. Its energy separation of similar to 2.5 eV from the U 5f UPS peak is larger than U-5f,U-5f = 1.2 eV This difference is interpreted as mostly due to the spin-orbit splitting of the U 5f state. The U 4f core XPS has shown rather an asymmetric shape with a tail toward larger binding energies (E(B)). A Satellite not directly observable in the experimental spectrum is revealed at similar to 5.4 eV by deconvolution. Based on an extended Anderson impurity model, it is interpreted as the ''p-d antibonding state.'' The appreciable density of the U 6d state near E(F) strongly influences the photoemission spectra.