08594 IUPAC Gold Book - electro-optic parameter 10.1351/goldbook.08594 08594 current initialism: EOP synonym: equilibrium charge, charge flux (ECCF) 1 Characteristic quantity used in the analysis of absolute infrared intensity data chosen on the assumption that the electric dipole moment of the molecule can be described as the vector sum of bond dipole moments. The original EOPs were \(\mu_{k}^{\circ}\), the equilibrium bond moment, and \(\partial \mu_{k}/\partial R_{t}\), the change in the electric dipole moment of bond \(k\) with change in internal displacement coordinate \(t\). A later and completely equivalent formulation uses equilibrium atomic charges, \(q_{\alpha}^{\rm{o}}\), and charge fluxes, \(\partial q_{\alpha}/\partial R_{t}\), which are also called EOPs as well as ECCF for equilibrium charge, charge flux. In Note 1, \(R\), are vibrational coordinates such as bond stretching, angle deformation, or torsion about a bond. PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 745 (https://doi.org/10.1515/pac-2019-0203) https://goldbook.iupac.org/terms/view/08594/html https://goldbook.iupac.org/terms/view/08594/json https://goldbook.iupac.org/terms/view/08594/plain Citation: 'electro-optic parameter' 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.08594 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. 2026-06-29T07:59:16+00:00