@article {381,
	title = {NMR with a continuously circulating flow of laser-polarized Xe-129},
	journal = {Journal of Physical Chemistry B},
	volume = {103},
	year = {1999},
	note = {J Phys Chem B203HNTimes Cited:45Cited References Count:35},
	month = {Jun 3},
	pages = {4629-4637},
	abstract = {<p>In this paper we describe the construction of an apparatus for optical pumping of Xe-129 in a circulating gas system connected to a probe for static high-field NMR. The optimal working conditions for the optical pumping under flow are explored, yielding a continuous gas now with a steady-state spin-polarization of about 2\%. It is shown that on various types of high surface area materials a steady-state of adsorbed laser-polarized xenon can be;reached with polarizations of about 0.3\%. NMR spectroscopy of this layer is greatly facilitated due to the renewable magnetization under the continuous-flow conditions allowing unprecedented fast detection of two-dimensional NMR experiments with laser-polarized Xe. The steady-state spin-polarization of adsorbed Xe-129 gives rise to cross-relaxation to surface nuclei such as H-1 and Si-29. A direct spin-polarization-induced nuclear Overhauser effect (SPINOE) to heteronuclei is observed with an enhancement factor of about 20-30. A method is presented for simple modulation of the spin-polarization direction in the fringe field of the high-field magnet; this is exploited to obtain difference SPINOE spectra to highlight only the surface nuclei. Furthermore, a transfer via cross-polarization (CP) from adsorbed Xe to surface protons is demonstrated to select surface groups with reduced mobility compared to SPINOE detection.</p>
},
	keywords = {zeolites},
	isbn = {1089-5647},
	doi = {Doi 10.1021/Jp9821984},
	url = {<Go to ISI>://WOS:000080702600011},
	author = {Seydoux, R. and Pines, A. and Haake, M. and Reimer, J. A.}
}
