WATER SELF-DIFFUSION IN LYOTROPIC SYSTEMS BY SIMULATION OF PULSED FIELD GRADIENT-SPIN ECHO NUCLEAR-MAGNETIC-RESONANCE EXPERIMENTS

In this paper the pulsed field gradient-spin echo nuclear magnetic resonance (PFG-SE) experiment has been performed by computer simulation technique. The diffusive phenomenon is reproduced by letting particles, moving only by Brownian motion, travel among reflecting aggregates; in such a way it is possible to calculate the nuclear magnetic resonance (NMR) echo attenuation due to the solvent self-diffusion in lyotropic systems overcoming the problem of the analytical determination of the probability distribution of the spins. The results obtained on lamellar and inverted hexagonal lyomesophases are in good agreement with the previous functions reported in literature and new results are given for the hexagonal phase treated using this approach; in particular a new interpolation formula for the determination of the obstruction factor as a function of the structural parameters is proposed.