Editing X-ray photoelectron spectroscopy (section)

===Peak identification===
The number of peaks produced by a single element varies from 1 to more than 20. Tables of binding energies that identify the shell and spin-orbit of each peak produced by a given element are included with modern XPS instruments, and can be found in various handbooks and websites.<ref>{{Cite web|title=X-Ray Data Booklet|url=https://xdb.lbl.gov/|access-date=2020-06-20|website=xdb.lbl.gov}}</ref><ref>{{cite web|title=Handbook of The Elements and Native Oxides|url=http://www.xpsdata.com/XI_BE_Lookup_table.pdf|access-date=8 December 2012|publisher=XPS International, Inc.}}</ref> Because these experimentally determined energies are characteristic of specific elements, they can be directly used to identify experimentally measured peaks of a material with unknown elemental composition.

Before beginning the process of peak identification, the analyst must determine if the binding energies of the unprocessed survey spectrum (0-1400 eV) have or have not been shifted due to a positive or negative surface charge. This is most often done by looking for two peaks that are due to the presence of carbon and oxygen.