double resonance 

https://doi.org/10.1351/goldbook.08333
Nuclear magnetic resonance spectroscopy experiment where excitation is applied independently to two distinct frequency ranges.
Note:
Double resonance is most commonly applied for spin decoupling.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 686 [Terms] [Paper]