Adsorption of hydrogen in Ca-exchanged Na-A zeolites probed by inelastic neutron scattering spectroscopy
- Los Alamos National Lab., NM (United States)
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
- ICI Films, Dumfries (United Kingdom)
- Argonne National Lab., IL (United States)
The hindered rotations and vibrations of molecular hydrogen, deuterium, and deuterium hydride adsorbed into partially and fully Ca ion exchanged Na-A zeolites have been studied at low temperatures with the use of inelastic neutron scattering (INS) techniques. A loading of one molecule per supercage was used in an attempt to avoid multiple site occupancies. Nonetheless, the INS spectra of the rotational transitions of H{sub 2}, HD, and D{sub 2} clearly show that physical adsorption occurs on several different sites. Both the CaNa-A and Ca-A samples have strong rotational bands near 6 meV. On this basis, we conclude that the principal adsorption site in CaNa-A is in the vicinity of the CA{sup 2+} cation where H{sub 2} experiences a rotational barrier of about 4.3 kJ/mol. 26 refs., 4 figs., 2 tabs.
- OSTI ID:
- 374472
- Journal Information:
- Journal of Physical Chemistry, Vol. 100, Issue 25; Other Information: PBD: 20 Jun 1996
- Country of Publication:
- United States
- Language:
- English
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