Theory of Spin Exchange between Optically Pumped Rubidium and Foreign Gas Nuclei

Herman, R. M.

doi:10.1103/physrev.137.a1062

Cited by 78 publications

(29 citation statements)

References 10 publications

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“…We obtain 0.45 ml s À 1 W À 1 for our device, again comparable to this quantity in large-scale polarizers 23 (see Supplementary Table 1). In this work, we employ the 87 Rb atoms as in situ detectors 13,18,19 of the 129 Xe magnetization and take advantage of the Fermi-contact interaction 13,[18][19][20][21] to enhance the detection sensitivity to 129 Xe by a factor of B500. This approach represents an important feature of our device that can be used to detect or monitor the 129 Xe polarization with high sensitivity at low magnetic fields in cases where the polarized gas can be cleanly extracted from the sample region.…”

Section: Discussionmentioning

confidence: 99%

Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip

et al. 2014

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Optically hyperpolarized 129 Xe gas has become a powerful contrast agent in nuclear magnetic resonance (NMR) spectroscopy and imaging, with applications ranging from studies of the human lung to the targeted detection of biomolecules. Equally attractive is its potential use to enhance the sensitivity of microfluidic NMR experiments, in which small sample volumes yield poor sensitivity. Unfortunately, most 129 Xe polarization systems are large and non-portable. Here we present a microfabricated chip that optically polarizes 129 Xe gas. We have achieved 129 Xe polarizations 40.5% at flow rates of several microlitres per second, compatible with typical microfluidic applications. We employ in situ optical magnetometry to sensitively detect and characterize the 129 Xe polarization at magnetic fields of 1 mT. We construct the device using standard microfabrication techniques, which will facilitate its integration with existing microfluidic platforms. This device may enable the implementation of highly sensitive 129 Xe NMR in compact, low-cost, portable devices.

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Section: Discussionmentioning

confidence: 99%

Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip

et al. 2014

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“…• It is thought that this term is particularly large for xenon due to polarization of the xenon core electron shells during a collision [97,98]. The polarization not transferred to the xenon is lost to the rotational angular momentum of the complex, N, which is subsequently dissipated as translational energy when the complex is broken up in another collision.…”

Section: Microscopic Picturementioning

confidence: 99%

Applications of highly spin-polarized xenon in NMR

Long

1993

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“…As shown by Herman [27], the Fermi contact interaction is enhanced in the rubidium-xenon complex due to the electron exchange interaction between the rubidium5s electron and the core s orbitals of xenon. The enhancement is on the order \ of 10 3 which can be derived by writing a Slater determinant for the rubidium valence electron with the xenon Is orbitals:…”

Section: (J) + [(!) :::} 8u) + [(J)mentioning

confidence: 99%

“…They considered the xenon-NO and xenon-02 collision pairs and determined that the Fermi-contact interaction was responsible in both cases for the unusually iarge resonance shifts observed in mixtures of these gases. Just as in the case of Rb-Xe [27], the valence electrons of the paramagnetic species have a large spin density at the xenon nucleus due to the enhancement by the Pauli exclusion principle.…”

Section: Xenon With Other Gasesmentioning

confidence: 99%

Optical pumping and xenon NMR

Raftery¹

1991

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Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for jnvestigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness . and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR " experiments, thereby allowing them to be Used in the study of systems with lower surface area.A novel method of optically-pumping 129Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described.NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically~ pumped xenon adsorbed onto polyacrylic acid show that xenon has alarge interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon.Experiments are also descriped that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupolar evolution of 131 Xe spins at the surface of the pumping cell~. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131XeNMR frequencies in bare Pyrex glass cells and cells with added hydrogen.Conventional xenon NMR experiments conducted on coadsorbed organic molecules _ in Na-Y zeolites show that the xenon chemical shift is sensitive to the identity and concentration of these guests. Clusters of xenon trapped in Na-A zeolite have interesting statistical distributions due to the finite atomic size of the xenon. The statistics can be described in the low to moderate loading regime by binary and hypergeometric distribution functions.Finally, a comprehensive review of the xenon NMR literature, including previous optical pumping studies, is provided.; ; "

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Theory of Spin Exchange between Optically Pumped Rubidium and Foreign Gas Nuclei

Cited by 78 publications

References 10 publications

Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip

Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip

Applications of highly spin-polarized xenon in NMR

Optical pumping and xenon NMR

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