CORRELATION OF VISCOSITY AND CONDUCTANCE WITH NA-23+ NMR T1 MEASUREMENTS

The relationship between rotational correlation time and the translational diffusion coefficient (Stokes-Einstein equation) of sodium ions dissolved in a series of water-glycerol solutions was studied. NMR longitudinal relaxation measurements gave an estimate of the rotational correlation time for the hydrated sodium ion. From this, using the Debye and Stokes-Einstein equations the translational diffusion coefficient was calculated. These results were compared with estimates of the sodium ion diffusion coefficient obtained using pulsed field gradient NMR. The simple, chemical system was chosen for this study so that the nature of the sodium relaxation would be unambiguous. Also, conductivity measurements were performed on each solution since the conductivity is intimately related to the rate of ionic diffusion. The results showed that due to the spherical nature of the hydrated sodium ion the Debye and Stokes-Einstein equations are well obeyed allowing translational diffusion coefficients to be calculated from rotational correlation times in good agreement with those measured using pulsed field gradient NMR. © 1990 The Chemical Society of Japan.