## σ → σ* transition

https://doi.org/10.1351/goldbook.S05435
An electronic transition described approximately as @P04877@ of an electron from a 'bonding' σ orbital to an 'antibonding' σ orbital designated as $$\sigma ^{\text{*}}$$. Such transitions generally involve high transition energies, and appear close to or mixed with @R05432@.
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2279 [Terms] [Paper]