Assigning chemical configurations to the XPS features observed at pristine (100) Si surface resulting after etching in HF aqueous solution

While the analysis of the spectra resulting from energy- or angle-resolved X-ray photoelectron spec- troscopy allows the in-depth atomic composition in the probed region to be determined even for complex samples, the determination of the bonding configuration is less trivial. In this paper it is shown that a description of the chemical shift in terms of partial charge and Madelung potential (as results from local modelling of the atom) can provide information even in complicate situations, like that characterizing the hydrogen-terminated (100) Si prepared by HFaq etching of the native oxide.