decaying more slowly than that expected from the rate of decay of the emitting state.
The following mechanisms of luminescence
triplet-triplet or singlet-singlet annihilation to form one molecular entity in its excited singlet state and another molecular entity in its electronic ground state (sometime referred to as P type),
- thermally activated delayed fluorescence involving reversible intersystem crossing (sometimes referred to as E type), and
combination of oppositely charged ions or of an electron and a cation. For emission to be referred to in this case as delayed luminescence at least one of the two reaction partners must be generated in a photochemical process.
PAC, 1988, 60, 1055
(Glossary of terms used in photochemistry (Recommendations 1988))
on page 1065
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook