Radiative deactivation of an excited state; transfer of energy from a molecular entity to an electromagnetic field.
See also: fluorescence, luminescence, phosphorescence
Source:
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2239 (https://doi.org/10.1351/pac199668122223)