Term: quenching
https://doi.org/10.1351/goldbook.Q05007

Definition:
deactivation of an excited molecular entity intermolecularly by an external environmental influence (such as a quencher) or intramolecularly by a substituent through a non-radiative process.

Notes:
0) When the external environmental influence (@Q05006@) interferes with the behaviour of the @E02257@ after its formation, the process is referred to as dynamic quenching. Common mechanisms include energy transfer, @E02011@, etc.
1) When the environmental influence inhibits the @E02257@ formation the process is referred to as static quenching.

Related Terms:
1) quencher (http://doi.org/10.1351/goldbook.Q05006).
2) excited state (http://doi.org/10.1351/goldbook.E02257).
3) electron transfer (http://doi.org/10.1351/goldbook.E02011).
4) deactivation (http://doi.org/10.1351/goldbook.D01528).

Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 407 (https://doi.org/10.1351/pac200779030293)

Citation: 'quenching' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.Q05007

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