Short-Time PFGSTE Diffusion Measurements

Abstract

The pulsed-field-gradient stimulated-echo method is a according to Fig. 1. This sequence has been shown to substantially remove or reduce signal following unwanted cowell-established technique for studying molecular motion without disturbing the system under investigation. In porous herence-transfer pathways without the need for orthogonal spoiler gradients (3) . media, the short-time expansion of the mean-squared displacement can be used to measure the surface-to-volume The echo attenuation for the sequence in Fig. 1 can be written as ratio, S /V, of a system (1) . Recently, Fordham et al. (2) showed that the effective diffusion time can be significantly altered by taking into account restricted diffusion during the ln I I0 A 0g (2d)g D( t)FD / 32 t 0 d 6G gradient pulses in the evaluation of the diffusion coefficient at short diffusion times. Using their corrected effective diffusion times, measurements of the surface-to-volume ratio of 1 F i 0 12 S D / t 0 d /6 D / 2t 0 d /6DxG 2 , [3] compact mono-sized spheres will be presented, and it will be shown that their model yields a better fit to the experimental data set. where the diffusion time is given by Mitra et al. (1) have shown that the diffusivity at short times, t , can be written as