Term: scattering vector https://doi.org/10.1351/goldbook.S05494 Definition: The vector difference between the wave propagation vectors of the incident and the scattered beam, both of length 2πλ, where λ is the wavelength of the scattered radiation in the medium. Related Terms: 1) propagation (http://doi.org/10.1351/goldbook.P04881). 2) wavelength (http://doi.org/10.1351/goldbook.W06659). Source: Purple Book, 1st ed., p. 65 (http://old.iupac.org/publications/books/author/metanomski.html) Citation: 'scattering vector' 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.S05494 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. 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.