X-ray levels have various degrees of
ionization -- single, double or higher -- and may in some cases also be electrically neutral.
An excitation level (
exciton) is an electrically neutral
X-ray level with an expelled electron bound in the field of a core electron vacancy.
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 738
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
