Field-cycling NMR relaxometry of liquids confined in porous glass: evidence for Levy-walks.

The frequency dependence of the longitudinal relaxation time T1 (v) of different liquids confined to microporous glass features a distinct difference between polar and nonpolar adsorbates. This finding is explained by "weak" and "strong" adsorption, respectively. The T1 dispersion of polar adsorbates can be described with the aid of Lévy walk statistics of "bulk-mediated surface diffusion" recently suggested by Bychuk and O'Shaughnessy.