## X-ray level

https://doi.org/10.1351/goldbook.X06715
An @ET07026@ occuring as the initial or final state of a process involving the absorption or emission of X-ray radiation. It represents a many-electron state which, in the purely atomic case, has total @A00353@ ($$J=L+S$$) as a well defined quantum number.
Source:
PAC, 1991, 63, 735. (Nomenclature, symbols, units and their usage in spectrochemical analysis - VIII. Nomenclature system for X-ray spectroscopy (Recommendations 1991)) on page 737 [Terms] [Paper]