Term: minimum-energy reaction path (MERP)
https://doi.org/10.1351/goldbook.M03931

Definition:
Path orthogonal to the equipotential contours of a potential energy surface that connects the energy minima through a saddle point (transition state) from which it slopes downwards along the steepest descending lines in 3N-6 configurational space (N is the number of nuclei in the reacting system).

Note: MERP calculation allows the investigation of detailed changes in molecular structure describing the @T06446@ of reactants to products.

Related Terms:
1) transformation (http://doi.org/10.1351/goldbook.T06446).
2) saddle point (http://doi.org/10.1351/goldbook.C01145).
3) transition state (http://doi.org/10.1351/goldbook.T06468).

Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 370 (https://doi.org/10.1351/pac200779030293)

Citation: 'minimum-energy reaction path (MERP)' 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.M03931

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