Determination of charge transfer in theCuxPd1−xalloy system

Measurements of the core-level binding energies and Auger kinetic energies of Cu and Pd in substitutionally disordered ${\mathrm{Cu}}_x{\mathrm{Pd}}_{1-x}$ alloys are analyzed in terms of the “correlated-charge model” (CCM), in which it is assumed that the charge on an atomic site is linearly dependent on its number of “unlike” nearest neighbors. This model has recently led to significant improvements in calculated total energies for random alloys. It is found that the measured core-level binding-energy shifts in the ${\mathrm{Cu}}_x{\mathrm{Pd}}_{1-x}$ alloy system are consistent with the average electrostatic potential of the random CCM lattice, given the degree of charge transfer predicted by ab initio calculations. We show experimentally that final-state relaxation energy shifts are small.