spin-statistical factor

in diffusion-controlled reactions
From the possible encounter pairs between states of different spin multiplicity, only those conserving multiplicity in going to products are expected to react.
This factor determines the efficiency of @D01716@-controlled reactions, which have an @E02089@. Typical examples are @Q05007@ of @F02453@ of aromatic @H02889@ by O2, @Q05007@ of triplet states by O2, and triplet–triplet @A00366@.
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 428 (https://doi.org/10.1351/pac200779030293)