One of the principal useful features of electron spectroscopy for chemical analysis (ESCA) is the identification of chemical states by the use of chemical shifts in the energies of photoelectron and Auger lines. For this purpose, the proper operation of electron spectrometers requires an accurate voltage scale. This can be checked with high accuracy, along with other important instrumental parameters, by recording the 2p_3/2 Auger, and 3p lines for clean copper.

The correction of energy data on insulators for steady-state static charges is best accomplished by noting the position of the adventitious carbon C-1s line, or by properly applying the gold decoration method. Data indicate that these methods are usually reproducible to approximately ±0.2 eV for homogenous compounds among different laboratories; reproducibility is better within any one laboratory. Energy corrections for insulating multiple phases pose special problems.