electron transfer process in which the reacting system has to cross over between different electronic surfaces in passing from reactants to products. For diabatic electron transfer the electronic transmission factor is ≪ 1 (see Marcus equation). The term non-adiabatic electron transfer has also been used and is in fact more widespread, but should be discouraged because it contains a double negation.
See also: adiabatic electron transfer
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2236 (https://doi.org/10.1351/pac199668122223)