XPS d bands and core levels of Pt-Ni alloys

Abstract

The photoemission spectra of the d bands and of the Ni 2p3/2 and Pt 4f core levels of Ni-Pt alloys have been measured with monochromatized X-rays. Within the 0.6 eV experimental resolution, the d band photoemission spectra appear to be described well by linear superpositions of the densities of states of the pure elements. The core level asymmetries of both Pt and Ni atoms change by no more than 20% with alloying, suggesting that they are not very sensitive to the magnetic state of the emitting atom nor to its local density of states near Ef, as determined by specific heat and susceptibility measurements. These results suggest that the core level asymmetries depend upon the local number of d holes, rather than the local density of states at the Fermi level. The core level asymmetries might provide a means to determine the number of d holes of certain atoms in alloys and compounds. It is suggested that the shape of the Ni 2p3/2 core level spectra might be determined by the occupied Ni 3d bands.