The displacement of photoelectron or Auger peak energies originating from changes in electron binding energies as a consequence of differences in the chemical environment of the atoms.
Source:
PAC, 1979, 51, 2243. 'General aspects of trace analytical methods—IV. Recommendations for nomenclature, standard procedures and reporting of experimental data for surface analysis techniques' on page 2247 (https://doi.org/10.1351/pac197951112243)