Anisotropic Xe chemical shifts in zeolites. The role of intra- and intercrystallite diffusion

We provide observations and interpretations of Xe-129 chemical shifts in open zeolite networks in which the Xe is in fast exchange among a large number of cavities and channels, in two zeolite types different from the A types that we have used before, and provide quantitative comparisons of adsorption isotherms and average Xe-129 chemical shifts using grand canonical Monte Carlo (GCMC) simulations employing the same methods and shielding functions used previously, We examine the temperature dependence of the Xe chemical shift at a fixed loading in NaY and silicalite and compare the predicted behavior with that of Xe-n in the alpha cages of NaA. Furthermore, we consider the most general case where the chemical shift reported by a Xe atom includes sampling environments in several crystallites and intercrystalline gas during acquisition of the NMR signal.