Rf-driven leakage of triple-quantum coherence in MAS NMR of spin-3/2 nuclei

By means of numerical simulations we further investigate the recently-observed phenomenon of rf-driven coherence leakage in MAS NMR of I = 3/2 quadrupolar nuclei. In particular, we focus our attention on the triple-quantum coherence leakage towards the single-quantum central-transition matrix element. We propose a simple 1D experiment that allows for the selective detection of single-quantum coherence solely stemming from such leakage. The offset from the carrier and rf-field strength may be tuned so that the resulting lineshapes are quasi-isotropic, with residual inhomogeneities possibly smaller than typical homogeneous broadenings. A qualitative relationship between the relevant parameters is given as guideline for the experimental setup.