{"term":{"id":"05862","title":"spin conservation rule","longtitle":"IUPAC Gold Book - spin conservation rule","doi":"10.1351\/goldbook.S05862","code":"S05862","status":"current","synonym":"<em>synonym<\/em>: Wigner rule","definitions":[{"id":1,"text":"For both radiative and radiationless transitions, the principle that transitions between terms of the same multiplicity are spin-allowed, while transitions between terms of different multiplicity are spin-forbidden.","sources":["Orange Book, 2nd ed., p. 185 (https:\/\/media.iupac.org\/publications\/analytical_compendium\/)","PAC, 1984, 56, 231. 'Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy' on page 234 (https:\/\/doi.org\/10.1351\/pac198456020231)","PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2277 (https:\/\/doi.org\/10.1351\/pac199668122223)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/S05862\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/S05862\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/S05862\/plain"},"citation":"Citation: 'spin conservation rule' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.S05862","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-05-30T20:17:27+00:00"}}