@article {476,
	title = {Nmr-Study of Xenon Dynamics and Energetics in Na-a Zeolite},
	journal = {Chemical Physics Letters},
	volume = {214},
	year = {1993},
	note = {Chem Phys LettMd614Times Cited:56Cited References Count:22},
	month = {Oct 29},
	pages = {220-226},
	abstract = {<p>For xenon atoms adsorbed in Na-A zeolite, electronic interactions cause shifts in NMR frequencies, resulting in a spectrum with discrete peaks from xenon atoms in cages with different xenon occupancies. Using two-dimensional exchange NMR, it is possible to determine the microscopic rates of intercage motion and to relate them to the adsorption and activation energies of the xenon atoms. The dependence of the adsorption energies on xenon cage occupancy reflects the importance of the intercage interactions and is directly related to the cage occupancy distribution. Variable temperature measurements yield an activation energy of about 60 kJ/mol for the transfer of a xenon from one cage to another.</p>
},
	keywords = {xe},
	isbn = {0009-2614},
	doi = {Doi 10.1016/0009-2614(93)90085-F},
	url = {<Go to ISI>://WOS:A1993MD61400015},
	author = {Larsen, R. G. and Shore, J. and Schmidt-Rohr, K. and Emsley, L. and Long, H. and Pines, A. and Janicke, M. and Chmelka, B. F.}
}
@article {511,
	title = {Nmr-Study of the Distribution of Aromatic-Molecules in Nay Zeolite},
	journal = {Journal of Physical Chemistry},
	volume = {95},
	year = {1991},
	note = {J Phys Chem-UsEr473Times Cited:70Cited References Count:64},
	month = {Jan 10},
	pages = {303-310},
	abstract = {<p>Local and macroscopic distributions of adsorbed benzene, 1,3,5-trimethylbenzene, and hexamethylbenzene (HMB) molecules among the intracrystalline of NaY zeolite samples have been investigated by Xe-129 and multiple-quantum NMR. Xenon-129 NMR, a sensitive probe of macroscopic distributions of molecules in zeolites at room temperature, demonstrates the importance of sample heat treatment in distributing an adsorbate homogeneously throughout a collection of zeolite particles. NaY samples containing organic guests adsorbed a temperatures near the bulk species\&$\#$39; melting point produce multiple or broad xenon lines characteristic of macroscopic (i.e., interparticle) adsorbate concentration gradients. After thorough heat treatment of the samples at elevated temperatures, the xenon spectrum collapses to a single sharp line, consistent with a macroscopically uniform distribution. For HMB adsorbed in NaY, \&quot;counting\&quot; hydrogen clusters by multiple-quantum NMR reveals intraparticle HMB distributions consistent with one molecular per cavity at low loadings (average bulk loading less-than-or-equal-to 1 molecule per cavity) and two molecules per cavity at higher loadings.</p>
},
	keywords = {catalysts},
	isbn = {0022-3654},
	doi = {Doi 10.1021/J100154a056},
	url = {<Go to ISI>://WOS:A1991ER47300056},
	author = {Chmelka, B. F. and Pearson, J. G. and Liu, S. B. and Ryoo, R. and Demenorval, L. C. and Pines, A.}
}
