Term: efficiency, \(\eta\)
https://doi.org/10.1351/goldbook.E01902

Definition:
The ratio between the useful energy delivered or bound and the energy supplied, i.e. energy output/energy input. It is also used in the sense of a quantitative measure of the relative rate of a given step involving a species with respect to the sum of the rates of all of the parallel steps which depopulate that species.

Related Terms:
1) quantum yield (http://doi.org/10.1351/goldbook.Q04991).

Source: PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2238 (https://doi.org/10.1351/pac199668122223)

Citation: 'efficiency, \(\eta\)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.E01902

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