The second order influence of the nuclear quadrupole interaction on the central line in the NMR of quadrupolar nuclei using rapid sample spinning

Abstract

Using perturbation theory it is demonstrated that the second order quadrupole broadening of the central line of the NMR spectra of half integer spins is reduced by rapid sample spinning at the magic angle down to about 1/3.6 of the original value. The centre of gravity of the central line remains unchanged. Thus, the method of rapid sample spinning at the magic angle in the NMR of nuclei with strong quadrupole couplings can be used to get directly the spatial average of the chemical shift tensor. This situation is demonstrated experimentally in the case of high-field 27Al- and 23Na-NMR of various materials.