Distributions of Site-Hopping Geometries and Rates for Benzene Adsorbed on Ag−Y Zeolite

Slow jump reorientation dynamics of benzene molecules adsorbed on Ag−Y zeolite (Si/Al = 2.4) have been investigated using solid-state nuclear magnetic resonance (NMR) spectroscopy. Multidimensional exchange 13 C NMR techniques establish that the benzene jump angle distribution is broad and that multiple benzene reorientation rates exist for site exchange among different local environments. Modeling of 2 H and 13 C NMR line shapes yields an apparent activation energy of 34 ± 2 kJ/mol and a preexponential factor of k 0 = 2 × 10 10 s -1 (± 1 / 2 decade) for the complicated molecular reorientation motions underlying benzene site-hopping dynamics in Ag−Y zeolite.