Title: radiative de-excitation
Long Title: IUPAC Gold Book - radiative de-excitation
DOI: 10.1351/goldbook.R05062
Status: current

Definition
The change in the internal energy of a particle may be due to radiative processes, i.e. the emission or absorption of a photon. A particle in an excited state 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 probability per second for a given excited particle is termed the transition probability for spontaneous emission.

Related Terms
- excited state: https://goldbook.iupac.org//terms/view/E02257
- internal energy: https://goldbook.iupac.org//terms/view/I03103
- probability: https://goldbook.iupac.org//terms/view/P04855
- spontaneous emission: https://goldbook.iupac.org//terms/view/S05886

Source
- PAC, 1985, 57, 1453. 'Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation sources (Recommendations 1985)' on page 1463 (https://doi.org/10.1351/pac198557101453)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/R05062/html
- json: https://goldbook.iupac.org/terms/view/R05062/json
- xml: https://goldbook.iupac.org/terms/view/R05062/xml

Citation: Citation: 'radiative de-excitation' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.R05062
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Accessed: 2026-08-01T20:58:30+00:00