Magic angle spinning NMR on single crystals as a new aid in characterizing phase transitions: application to squaric acid

1997 ◽  
Vol 104 (4) ◽  
pp. 651-656 ◽  
Author(s):  
A. N. Klymachyov ◽  
N. S. Dalal
Keyword(s):  
Phase Transitions ◽  
Single Crystals ◽  
Magic Angle Spinning ◽  
Squaric Acid ◽  
Magic Angle ◽  
Angle Spinning

High resolution triple resonance micro magic angle spinning NMR spectroscopy of nanoliter sample volumes

2016 ◽  
Vol 18 (6) ◽  
pp. 4902-4910 ◽  
Author(s):  
J. Ole Brauckmann ◽  
J. W. G. (Hans) Janssen ◽  
Arno P. M. Kentgens
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
High Resolution ◽  
Single Crystals ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Triple Resonance ◽  
Angle Spinning

To be able to study mass-limited samples and small single crystals, a triple resonance micro-magic angle spinning (μMAS) probehead for the application of high-resolution solid-state NMR of nanoliter samples was developed.

PbO / PbF2 Flux Growth of YScO3 and LaScO3 Single Crystals – Structure and Solid-State NMR Spectroscopy

2010 ◽  
Vol 65 (10) ◽  
pp. 1199-1205 ◽  
Author(s):  
Sarkarainadar Balamurugan ◽  
Ute Ch. Rodewald ◽  
Thomas Harmening ◽  
Leo van Wüllen ◽  
Daniel Mohr ◽  
...  
Keyword(s):  
Rare Earth ◽  
Solid State ◽  
Single Crystals ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Flux Growth ◽  
Quadrupolar Interaction ◽  
Angle Spinning ◽  
Good Agreement

Well-shaped small single crystals of the orthorhombic perovskites YScO3 and LaScO3 were grown from mixtures of the corresponding sesquioxides RE2O3 in PbO/PbF2 fluxes. Both structures were refined from single-crystal diffractometer data: GdFeO3-type, Pnma, a = 570.68(7), b = 789.3(1), c = 542.44(7) pm, wR2 = 0.0363, 448 F2 values for Y0.96ScO2.94, and a = 579.68(9), b = 810.3(2), c = 568.3(1) pm, wR2 = 0.0387, 513 F2 values for La0.94ScO2.91, with 32 variables per refinement. The 4c rare-earth sites of both perovskites show small defects which are charge-compensated by defects on both oxygen sites, leading to the compositions La0.94ScO2.91 and Y0.96ScO2.94 for the investigated crystals. The rare-earth sites have been characterized by 89Y and 45Sc magic-angle spinning (MAS) NMR. The 45Sc quadrupolar interaction parameters extracted from these spectra by simulations are found to be in good agreement with those obtained from DFT calculations of the electric field gradient.

Pulse Shaped Dynamic Nuclear Polarization Under Magic Angle Spinning

2019 ◽  
Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han
Keyword(s):  
Electron Spin ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Total Electron ◽  
Spin Lattice ◽  
Maximum Benefit ◽  
Selective Saturation ◽  
Angle Spinning

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.

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