Electronic transition which is adequately described by single electron transfer between a solute and the solvent, as opposed to excitation followed by electron transfer to solvent.
See also: charge-transfer transition
Source:
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2232 (https://doi.org/10.1351/pac199668122223)