spin decoupling 

https://doi.org/10.1351/goldbook.08419
Irradiation of a nucleus in nuclear magnetic resonance spectroscopy to prevent spin-spin coupling.
See also: heteronuclear decoupling, homonuclear decoupling
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 705 (https://doi.org/10.1515/pac-2019-0203)