Term: dividing surface
https://doi.org/10.1351/goldbook.D01823

Definition:
A surface, usually taken to be a hyperplane, constructed at right angles to the minimum-energy path on a potential-energy (reaction) surface. In conventional transition-state theory it passes through the highest point on the minimum-energy path. In generalized versions of transition-state theory the dividing surface can be at other positions; in variational transition-state theory the position of the dividing surface is varied so as to get a better estimate of the rate constant.

Related Terms:
1) minimum-energy path (http://doi.org/10.1351/goldbook.M03931).
2) potential-energy (reaction) surface (http://doi.org/10.1351/goldbook.P04780).
3) transition-state theory (http://doi.org/10.1351/goldbook.T06470).
4) variational transition-state theory (http://doi.org/10.1351/goldbook.V06603).
5) rate constant (http://doi.org/10.1351/goldbook.O04322).

Source: PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 163 (https://doi.org/10.1351/pac199668010149)

Citation: 'dividing surface' 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.D01823

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