π → σ* transition

https://doi.org/10.1351/goldbook.S04387
An electronic transition described approximately as a @[email protected] of an electron from a 'bonding' orbital π to an 'antibonding' orbital σ designated as σ*. Such transitions generally involve high transition energies and appear close to or mixed with @[email protected]
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2266 [Terms] [Paper]