radiative de-excitation

in spectrochemistry
Also contains definition of: transition probability for spontaneous emission in spectrochemistry
https://doi.org/10.1351/goldbook.R05062
The change in the @[email protected] of a particle may be due to radiative processes, i.e. the emission or absorption of a photon. A particle in an @[email protected] may undergo a transition to a lower energy level by emission of a photon. This is known as radiative de-excitation. If such a transition occurs spontaneously its @[email protected] per second for a given excited particle is termed the transition @[email protected] for @[email protected]
Source:
PAC, 1985, 57, 1453. (Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation sources (Recommendations 1985)) on page 1463 [Terms] [Paper]