05306 IUPAC Gold Book - repulsive potential-energy surface 10.1351/goldbook.R05306 R05306 current synonym: late-downhill surface 1 A surface for an exergonic reaction $\ce{A + BC}$ in which the col corresponds to considerable separation between the products $\ce{A–B + C}$. The energy barrier in the potential-energy profile is in the later stages of the reaction path. On such a surface most of the energy is released after $\ce{A–B}$ is formed. Repulsive surfaces are also called late-downhill surfaces, and the barrier in such a surface is called a Type-II barrier. exergonic reaction https://goldbook.iupac.org//terms/view/E02262 potential-energy profile https://goldbook.iupac.org//terms/view/P04779 reaction path https://goldbook.iupac.org//terms/view/R05174 PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 185 (https://doi.org/10.1351/pac199668010149) https://goldbook.iupac.org/terms/view/R05306/html https://goldbook.iupac.org/terms/view/R05306/json https://goldbook.iupac.org/terms/view/R05306/plain Citation: 'repulsive potential-energy surface' 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.R05306 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-04-19T00:15:24+00:00