Simultaneous electronic transitions in two coupled absorbers or emitters. Because of the @C01025@, transitions which are spin-forbidden in one of the centres might become spin-allowed (spin flip).
Source: PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2273 [Terms] [Paper]
Citation: 'simultaneous pair transitions' in IUPAC Compendium of Chemical Terminology, 3rd ed. International Union of Pure and Applied Chemistry; 2006. Online version 3.0.1, 2019. https://doi.org/10.1351/goldbook.S05679 RISBibTexEndNote