Title: threshold energy
Long Title: IUPAC Gold Book - threshold energy
DOI: 10.1351/goldbook.T06366
Status: current
Index: quantity

Definition
Potential energy gap between reactants and the transition state, sometimes involving the zero point energies, but usually not.

Related Terms
- critical energy: https://goldbook.iupac.org//terms/view/C01393
- reactants: https://goldbook.iupac.org//terms/view/R05163
- transition state: https://goldbook.iupac.org//terms/view/T06468

Sources
- Green Book, 2nd ed., p. 56 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
- PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 189 (https://doi.org/10.1351/pac199668010149)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/T06366/html
- json: https://goldbook.iupac.org/terms/view/T06366/json
- xml: https://goldbook.iupac.org/terms/view/T06366/xml

Citation: Citation: 'threshold energy' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.T06366
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Accessed: 2026-06-20T02:09:17+00:00