X-ray photoemission lineshapes and energies in PdxCu1-x

Measurements of core and valence level X-ray photoemission spectra are reported for a series of ten Pd x Cu 1-x alloys with varying compositions. The core level binding energy shifts display a distinct dichotomy in behaviour at x approximately=0.4. For x<or=0.4 the Pd shifts are zero within experimental error (+or-0.1 eV), which the authors interpret as resulting from the equality of the Fermi energy of the alloy and of Pd, which implies negligible charge transfer. For x>0.4, the Pd shifts are consistent with a Fermi level different from that of pure Pd. The systematics of the Pd core level lineshapes are shown to be in accordance with this interpretation.