quenching of an excited atom or molecular entity by interaction with another atom or molecular entity of the same species in the ground state.
See also: Stern–Volmer kinetic relationships
Source:
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2273 (https://doi.org/10.1351/pac199668122223)