TRIPLE-QUANTUM MAS-NMR OF QUADRUPOLAR NUCLEI

From two-dimensional multiquantum NMR spectra of quadrupolar nuclei, i t is now possible to obtain much greater resolution than in a classica l single-quantum magic-angle spinning or variable-angle spinning spect rum. We describe here a very simple pulse scheme which efficiently exc ites the desired multiquantum NMR coherence and a new acquisition proc edure which yields to pure-absorption mode 2D spectra. Experimental sp ectra for Rb-87 in polycrystalline rubidium nitrate illustrate the met hod.