Title: force field
Long Title: IUPAC Gold Book - force field
DOI: 10.1351/goldbook.11446
Status: current

Definition
A set of mathematical functions and their associated parameters used in a molecular mechanics or dynamics calculation of conformations, flexibility, and interactions of molecules.

Note
Within the molecular mechanics approach, a set of potential functions defining bond stretch, bond angle (both valence and dihedral) distortion energy of a molecule as compared with its nonstrained conformation (that characterized by standard values of bond lengths and angles). A set of transferable empirical force constants is preassigned and the harmonic approximation is usually employed. Some force fields may contain terms for interactions between non-bonded atoms, electrostatic, hydrogen bond and other structural effects as well as account for anharmonicity effects. In vibrational spectroscopy, the inverse problem is solved of determining a set of force constants and other parameters of a chosen potential energy functions which would match with experimentally observed vibrational frequencies of a given series of congeneric molecules.

Source
- PAC, 2016, 88, 239. 'Glossary of terms used in computational drug design, part II (IUPAC Recommendations 2015)' on page 246 (https://doi.org/10.1515/pac-2012-1204)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/11446/html
- json: https://goldbook.iupac.org/terms/view/11446/json
- xml: https://goldbook.iupac.org/terms/view/11446/xml

Citation: Citation: 'force field' 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.11446
License: 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.
Collection: If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .
Disclaimer: 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.
Accessed: 2026-06-12T14:51:37+00:00