Xenon NMR spectroscopy has become an important and widely used tool for characterizing complex chemical systems and host phases. Issues central to new and existing uses of xenon NMR in materials research are emphasized, including xenon mass transport considerations, the sensitivity of xenon’s NMR parameters to local and macroscopic material structure and dynamics, and novel optical polarization techniques. After reviewing the foundations of 129Xe and 131Xe NMR spectroscopy methods, a number of applications are presented, particularly those focusing on new developments in the field.

Xenon NMR Spectroscopy

Chemical shielding tensors have been determined for 13C in single crystals of ammonium D‐tartrate using proton‐enhanced NMR. The unit cell contains two molecules, and in some orientations eight lines are resolved from the eight magnetically inequivalent carbon nuclei. Details of the experimental approach, equipment, and analysis are provided, and results are presented for three determinations on two single crystals. These indicate a precision of ±2 ppm in the determination of the principal values and ±3° in the orientation of the principal axes for the carboxyl groups, with lower precision for the hydroxyl groups. The orientations of the principal axes of the tensors are related to the crystallographic (a, b, c*) axes by employing orientation data from x‐ray precession work in this study. The most plausible assignment of the tensors to particular 13C nuclei in the unit cell indicates that the heaviest shielding for 13C in the carboxyl groups occurs when H0 is perpendicular to the carboxyl plane and the li...

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Carbon‐13 nuclear magnetic resonance in solid ammonium tartrate

https://escholarship.org/content/qt0vm1x1qx/qt0vm1x1qx.pdf?t=p21o1e

Experimental results on deuterium NMR in the solid state by magic angle sample spinning

Homogeneous and inhomogeneous nuclear spin echoes in organic solids: Adamantane

Using a spin-temperature approach, we describe a scheme of adiabatic cross polarization, based on demagnetization/remagnetization, when the Zeeman order of abundant nuclei in the laboratory frame is first adiabatically converted into the dipolar order, and then, into the Zeeman order of rare nuclei. The scheme, implemented with two low-power frequency-sweeping pulses, is very efficient for static samples and can significantly increase polarization of rare nuclei, compared to the conventional Hartmann–Hahn cross polarization. The experimental examples are presented for a solid, liquid crystal, and small molecules in a liquid-crystalline solvent.

Thermodynamics of adiabatic cross polarization

https://escholarship.org/content/qt3hm7d1fq/qt3hm7d1fq.pdf?t=p0hiqh

Enhanced inhomogeneous nuclear spin echoes for dilute spins in solids

Concepts and results are presented which indicate not only that high resolution spin-1 NMR is possible but also that a whole new range of spin physics is open. The operator theory of double quantum NMR is given and some experiments are described. (GHT)

/pdf/double-quantum-nmr-in-solids-36psi5zlm3.pdf

T.W. Shattuck

Papers

Enhanced inhomogeneous nuclear spin echoes for dilute spins in solids

Double quantum nmr in solids