Temperature dependence of nuclear magnetic resonance chemical shifts of Xe-129 in the alpha-cages of NaY zeolite

One- and two-dimensional NMR spectra of Xe-129 sorbed in NaY zeolite at a l oading of approximately 1 Xe atom/4 alpha-cages were obtained as a function of temperature. One-dimensional spectra were measured over the range of 60 -300 K, by far the largest range yet investigated with this method. The dat a were fitted to the simple statistical mechanical cylindrical pore model o f Cheung yielding a van der Waals adsorption energy of 3.3 kJ/mol. 2D-NOESY spectra were obtained at 300 and 355 K. The two-dimensional data show that the intercrystalline diffusion is slow compared to intracrystalline diffus ion. The results indicate that the Xe atoms spend most of their time in the or-cages and at the lower temperatures, near the cage walls.