{"term":{"id":"08837","title":"lowest unoccupied molecular orbital","longtitle":"IUPAC Gold Book - lowest unoccupied molecular orbital","doi":"10.1351\/goldbook.08837","code":"08837","status":"current","acronym":"<em>acronym<\/em>: LUMO","definitions":[{"id":1,"text":"Lowest-energy molecular orbital that is unoccupied in the ground state but occupied by one or more electrons if the molecular entity occurs in its first electronically excited state.","links":[{"term":"energy band theory","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/08811"},{"term":"molecular orbital theory","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/08841"}],"sources":["PAC, 2022, 94, 15. 'Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)' on page 37 (https:\/\/doi.org\/10.1515\/pac-2020-0501)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/08837\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/08837\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/08837\/plain"},"citation":"Citation: 'lowest unoccupied molecular orbital' 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.08837","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":"2026-06-07T01:21:43+00:00"}}