08343 IUPAC Gold Book - flip angle 10.1351/goldbook.08343 08343 current synonym: tip angle 1 Rotation that the net magnetization experiences during the application of a radiofrequency pulse in nuclear magnetic resonance spectroscopy. For a strong and rectangular RF-pulse of constant amplitude (\(B_{1}\)) and duration (\(t_{\rm{p}}\)), the resultant flip angle is approximately proportional to the frequency (\(f_{1}\)) of the \(B_{1}\) field: \(\alpha = \gamma B_{1} t_{\rm{p}}\), where \(\gamma\) is the gyromagnetic ratio. nuclear magnetic resonance spectroscopy https://goldbook.iupac.org//terms/view/08218 radiofrequency https://goldbook.iupac.org//terms/view/08279 PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 688 (https://doi.org/10.1515/pac-2019-0203) https://goldbook.iupac.org/terms/view/08343/html https://goldbook.iupac.org/terms/view/08343/json https://goldbook.iupac.org/terms/view/08343/plain Citation: 'flip angle' 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.08343 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. 2026-07-29T17:32:33+00:00