initial energy state

in Auger electron spectroscopy
https://doi.org/10.1351/goldbook.09338
Ground state of an atom prior to photoelectron emission.
Source:
PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1826 (https://doi.org/10.1515/pac-2019-0404)