Reorientational and translational dynamics of benzene in zeolite NaY as studied by one- and two-dimensional exchange spectroscopy and static-field-gradient nuclear magnetic resonance

Abstract

One- and two-dimensional H2- and C-NMR13 (nuclear magnetic resonance) echo spectroscopy and H1 static field gradient NMR self-diffusion experiments have been used to study the reorientational and translational dynamics of benzene molecules adsorbed on zeolite NaY as a function of loading. Comparison of the data with model calculations establish that the elementary motional process of the guest molecules is consistently identified as a jump process among well defined adsorption sites inside a supercage and/or a jump between nearby supercages. In cases where the zeolite cavities contain high loadings of guest molecules, each molecular jump is accompanied by concomitant relaxation of the local environment. Molecular jump events between adsorption sites correspond to the elementary processes from which long range translational diffusion evolves.