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|Type:||Artigo de periódico|
|Title:||Noble Metal Auger Spectroscopy As A Probe Of Electronic Structure: Mapping Fermi Energies In Trimetallic Alloys|
de Castro S.G.C.
|Abstract:||XPS binding energy shifts in alloys are sensitive to valence occupation changes. Since binding energies are defined relative to the Fermi energy, exploitation of this property of the shifts has been hampered by ignorance of relative Fermi energies. Application of the quasiatomic model of screening shows that, for noble metal atom N in bimetallic alloy AxN1-x, in the absence of charge transfer, the Auger kinetic energy shift, ΔKN (x) ≅ -ΔEFN (x), the Fermi energy relative to that of pure metal N. Study of a number of such alloys demonstrates the validity of the relation, allowing one to adduce little charge transfer and, for Au-Pd, to determine valence occupation changes. These results suggest the possibility of probing the relative Fermi energy in a general random alloy by measuring the Auger shift of a noble metal impurity. Validity of this relation implies that the difference between the Auger shifts of different impurities should be constant independent of concentration. Here we report XPS and Auger spectroscopy measurements of trimetallic alloys with low concentrations of noble metal N (N = either Ag or Cu). Ag, Cu and Au Auger shifts in AuxPdyNz alloys are consistent with these ideas and with previous results. © 1991.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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