09288 IUPAC Gold Book - standard vacuum level 10.1351/goldbook.09288 09288 current mentioned: Fermi level 1 Electric potential \(\pu{4.500 eV}\) above the Fermi level. The Fermi level is an absolute level to which electron kinetic energies can be accurately referenced. Historically, in Auger electron spectroscopy, the electron energies have not been referenced to the Fermi level but, instead, have been referenced to the instrument vacuum level. This level varies from instrument to instrument and does not provide a consistent reference level. However, most reported Auger electron kinetic energies have been referenced to the vacuum level, and most analysts are familiar with the variations that occur from one instrument to another for energies referenced in this way. By convention, the standard vacuum level is defined, as above, to be a consistent reference level close to the value for typical instrument vacuum levels. Energies referenced to the standard vacuum level are consistent and are within approximately \(\pu{1 eV}\) of those referenced to individual instrument vacuum levels. Auger electron spectroscopy https://goldbook.iupac.org//terms/view/09172 vacuum level https://goldbook.iupac.org//terms/view/09300 PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1814 (https://doi.org/10.1515/pac-2019-0404) https://goldbook.iupac.org/terms/view/09288/html https://goldbook.iupac.org/terms/view/09288/json https://goldbook.iupac.org/terms/view/09288/plain Citation: 'standard vacuum level' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09288 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-07-26T13:48:04+00:00