Abstract
Solid-state exchange NMR has been used to measure directly discrete intercage hopping of strongly adsorbed molecules on a nanoporous zeolite. Such intercage motions represent the molecular transport events that are central to macroscopic diffusion of guest molecules through zeolite pore spaces. Apparent activation energies of 73 and have been measured for intra- and intercage hopping, respectively, of benzene molecules on Ca-Y zeolite. Exchange NMR measurements at 338 to 368 K yield benzene self-diffusion coefficients from , values which are well below the range of diffusivities accessible from other equilibrium techniques.
- Received 24 July 1998
DOI:https://doi.org/10.1103/PhysRevLett.81.5852
©1998 American Physical Society