03111 IUPAC Gold Book - internal valence force field 10.1351/goldbook.I03111 I03111 current initialism: IVFF 1 A force field expressed in terms of bond-stretching, angle-bending, torsional and other displacements directly connected to the structural parameters of the molecule: \[V=\frac{1}{2}\ \sum k_{ij}\ R_{i}\ R_{j}\] or \[V=\frac{1}{2}\ \sum K_{ij}\ R_{i}\ R_{j}\] where \(k\) (or \(K\)) are the force constants and \(R\) the internal valence coordinates. angle https://goldbook.iupac.org//terms/view/A00346 force constants https://goldbook.iupac.org//terms/view/F02481 valence https://goldbook.iupac.org//terms/view/V06588 PAC, 1978, 50, 1707. 'Definition and Symbolism of Molecular Force Constants' on page 1709 (https://doi.org/10.1351/pac197850111707) https://goldbook.iupac.org/terms/view/I03111/html https://goldbook.iupac.org/terms/view/I03111/json https://goldbook.iupac.org/terms/view/I03111/plain Citation: 'internal valence 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.I03111 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. 2026-04-23T22:37:04+00:00