DETERMINATION OF THE DIPOLAR INTERACTION OF NA-23 IN SOLUTION BY TRIPLE-QUANTUM RELAXATION-TIME MEASUREMENTS

The measurement of the dipolar interaction of Na-23 with hydrogen nucl ei in glycerol solution is reported. The method, applied previously to Li-7 (U. Eliav and G. Navon, J. Magn. Reson. A 123, 32 (1996)), is ba sed on the measurement of the triple-quantum relaxation time of Na-23. Several models of motion are discussed. The analysis of the results y ielded 1.9 MHz and 12.5 kHz for the quadrupolar and the Na-23-H-1 dipo lar interaction, respectively. It is shown that under the conditions o f long correlation times the triple-quantum relaxation time can be sen sitive to dipolar interactions smaller than the quadrupolar interactio n by as much as a factor of 5000. This indicates the possibility of me asuring interatomic distances for nuclei with sizable quadrupolar mome nts. (C) 1998 Academic Press.