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
See also: Orange Book, p. 185
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