The radiative decay of an excitation level may proceed to the neutral ground state
and would thus occur at the same energy as the corresponding line in the absorption spectrum
. Such a line is called a resonance
line and the process is called resonance emission.
PAC, 1991, 63, 735
(Nomenclature, symbols, units and their usage in spectrochemical analysis - VIII. Nomenclature system for X-ray spectroscopy (Recommendations 1991))
on page 739
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. doi:10.1351/goldbook