spin-statistical factor

in diffusion-controlled reactions
https://doi.org/10.1351/goldbook.ST07482
From the possible @E02086@ pairs between states of different spin multiplicity, only those conserving multiplicity in going to products are expected to react.
Note:
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@.
Source:
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 428 [Terms] [Paper]