We report the results of x-ray photoemission (XPS) and Auger electron spectroscopies in the alloy Au Pd& " for various concentrations. By comparing the predictions of the excited-atom version of the quasiatomic model with the dilute Au results, we show that charge-transfer corrections to the Au Auger kinetic-energy shift, hc. ;,k, are sma11. This result supports the validity of the relation be~k = bErA" -=EP "-EF(x-) [where EP " and EF(x) are the Fermi energies in pure Au and the alloy, respectively] and permits determination of the order of magnitude of the charge transfer from Auger measurements alone (i.e. , hundredths of electrons/atom). Such small charge transfer seems to hold also for the Ag and Cu atoms in Pd-Ag, Au-Ag, Pd-Cu, and Au-Cu. Furthermore, these results are consistent with interpretation of the Au Auger parameter shift, bg~", as well as with analysis of Ace ", the valence-electron contribution to the Au XPS core binding energy; we predict that bg=bco for noble metals in general. This analysis yields the result that the dilute Au dvalence-electron occupations change = -0.2 electrons/atom, approximately the negative of the sp change from isomer shifts. The Pd results are consistent with small charge transfer and a small gain of d electrons.

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We present X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) investigations of ordered chromium oxide ultrathin films prepared on a Pd(111) single-crystal surface.