Decoupling-induced recoupling in multiple-quantum magic-angle-spinning NMR spectra of quadrupolar nuclei

We report the observation of a new decoupling-induced recoupling phenomenon in multiple-quantum magic-angle-spinning (MQMAS) NMR spectra of half-integer quadrupolar nuclei. The origin of the effect is identical to the second-order recoupling between dipolar and anisotropic chemical shielding interactions under continuous-wave (CW) spin decoupling, which is first observed by Ernst et al. in the solid-state NMR spectra of spin-1/2 nuclei [J. Chem. Phys. 105 (1996) 3387].