From the Au 4f and Si 2p core level photoemission measurements of Au/Si(100), it is found that both core levels exhibit positive binding energy shifts when they form chemical bonds. The Si 2p shift is interpreted in terms of electronegativity difference, while the Au 4f shift is attributed to d-electron depletion to form an sd hybrid. © 1993.
Lu, Z. H., Sham, T. K., & Norton, P. R. (1993). Interaction of Au on Si(100) studied by core level binding energy shifts. Solid State Communications, 85(11), 957–959. https://doi.org/10.1016/0038-1098(93)90712-V