The effective nuclear spin-lattice relaxation mechanism has been determined in a number of crystals by observing the relative saturation behaviour of the lines of their quadrupole-split nuclear magnetic resonance spectra. It is shown that all lines and combinations of lines should have the same saturation behaviour if the mechanism is magnetic, and differing behaviour if the mechanism is quadrupolar. The 23 Na relaxation in pure synthetic crystals of sodium nitrate, sodium chlorate and sodium thiosulphate was found in each case to be quadrupolar. The 7 L1 and 27 Al relaxation in natural mineral crystals of spodumene and the 27 Al relaxation in a mineral crystal of euclase were found to be magnetic. The 11 B relaxation in a pure synthetic crystal of borax was also found to be magnetic. Chemical analysis showed a sufficient concentration of paramagnetic impurity in the mineral specimens to account for the dominance of the magnetic relaxation mechanism, and a sufficiently small concentration of paramagnetic impurity in the three sodium salts to account for the dominance of the quadrupolar mechanism. Despite the purity of the borax crystal, the quadrupole moment of the 11 B nuclei is too small to enable the quadrupolar mechanism to compete with the magnetic mechanism.
No takes yet. Share an insight, caveat, or question.
Andrew et al. (1960) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: