Palladium binding energy shift

Room temperature deposition of silver on Pd(lOO) produces a rather sharp Ag/Pd interface [62]. The interaction with a palladium surface induces a shift of Ag 3d core levels to lower binding energies (up to 0.7 eV) while the Pd 3d level BE, is virtually unchanged. In the same time silver deposition alters the palladium valence band already at small silver coverage. Annealing of the Ag/Pd system at 520 K induces inter-diffusion of Ag and Pd atoms at all silver coverage. In the case when silver multilayer was deposited on the palladium surface, the layered silver transforms into a clustered structure slightly enriched with Pd atoms. A hybridization of the localized Pd 4d level and the silver sp-band produces virtual bound state at 2eV below the Fermi level. 

The redistribution of charge and d- s,p rehybridisation observed in many theoretical calculations [23,33,34,37-39,40,41,48,98] should affect the position of the core levels and valence band of palladium. The Pd(4d) orbitals are more compact than the Pd(5s,5p) orbitals and, therefore, exhibit larger Coulomb interactions with the core electrons of palladium [23,60,99,100], Thus, a d-s,p rehybridisation reduces electron-electron repulsion and should shift the Pd core levels and 4d band toward higher binding energy [51,60],... 

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