scholarly journals Structural Analysis of Polyethylene Fibers by Solid State High Resolution NMR; the Distribution of 13C Spin-Lattice Relaxation Times

1990 ◽  
Vol 22 (10) ◽  
pp. 893-900 ◽  
Author(s):  
Atsushi Kaji ◽  
Atsuhiko Yamanaka ◽  
Masao Murano
Keyword(s):  
Solid State ◽  
Structural Analysis ◽  
High Resolution ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
High Resolution Nmr ◽  
Polyethylene Fibers

scholarly journals Observation of an environmentally insensitive solid-state spin defect in diamond

Science ◽  
2018 ◽  
Vol 361 (6397) ◽  
pp. 60-63 ◽  
Author(s):  
Brendon C. Rose ◽  
Ding Huang ◽  
Zi-Huai Zhang ◽  
Paul Stevenson ◽  
Alexei M. Tyryshkin ◽  
...  
Keyword(s):  
Solid State ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Zero Phonon Line ◽  
Spin Lattice ◽  
Network Applications ◽  
Field Noise ◽  
Quantum Science ◽  
State Spin

Engineering coherent systems is a central goal of quantum science. Color centers in diamond are a promising approach, with the potential to combine the coherence of atoms with the scalability of a solid-state platform. We report a color center that shows insensitivity to environmental decoherence caused by phonons and electric field noise: the neutral charge state of silicon vacancy (SiV0). Through careful materials engineering, we achieved >80% conversion of implanted silicon to SiV0. SiV0 exhibits spin-lattice relaxation times approaching 1 minute and coherence times approaching 1 second. Its optical properties are very favorable, with ~90% of its emission into the zero-phonon line and near–transform-limited optical linewidths. These combined properties make SiV0 a promising defect for quantum network applications.

Keto-Enol Tautomerism of Dimedone Studied by Dynamic NMR

1996 ◽  
Vol 50 (11) ◽  
pp. 1408-1412 ◽  
Author(s):  
Antonio Martínez-Richa ◽  
Guillermo Mendoza-Díaz ◽  
Pedro Joseph-Nathan
Keyword(s):  
High Resolution ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Tautomeric Equilibrium ◽  
Spin Lattice Relaxation ◽  
Exponential Factor ◽  
Spin Lattice ◽  
C Nmr ◽  
Coalescence Temperature

The keto-enol tautomeric equilibrium of dimedone has been investigated by high-resolution 13C NMR spectroscopy. Kinetic information of the solution keto-enol tautomerism for dimedone in DMSO, in the temperature range of 25–85 °C, was derived from line shape measurements in a 75-MHz spectrometer. A value of 3.43 Kcal/mol was found for the Arrhenius activation energy Ea and of 1.07 × 106 s−1 for the pre-exponential factor A. With the use of the observed chemical shifts in the high-resolution 13C-NMR spectra of dimedone in the solid state, an estimate coalescence temperature of 240 K for dimedone in DMSO was obtained by extrapolation of the experimental curve. The estimated free energy of activation at the coalescence temperature, Δ Gc≠, is 10.8 Kcal/mol. Finally, the 13C spin-lattice relaxation times, T1(13C), in solid dimedone were measured as a function of temperature in the range of 25 to 90 °C. The data are discussed in terms of the different motional environments that result from the geometric restrictions imposed by hydrogen bonding in the crystal structure.

Solid-state 2H NMR study of methyl-d3-cobalamin

1998 ◽  
Vol 76 (2-3) ◽  
pp. 423-428 ◽  
Author(s):  
Jennifer R Garbutt ◽  
Gillian R Goward ◽  
Christopher W Kirby ◽  
William P Power
Keyword(s):  
Solid State ◽  
Rotational Diffusion ◽  
Group Analysis ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Methyl Group ◽  
Spin Lattice ◽  
H Nmr ◽  
Nmr Study

A solid-state 2H NMR study of methyl-d3-cobalamin has been performed as a function of temperature to provide information concerning the character and energetics of the motion performed by this unique bioorganometallic methyl group. Analysis of the 2H NMR line shape indicates that the methyl group undergoes rapid three-fold rotation, and that the Co-C-2H angle lies between 105.9 and 109.5°. Determination of the spin-lattice relaxation times T1 shows that the relaxation is anisotropic, consistent with a "jumping" motion of the methyl group rather than rotational diffusion. This also provides the activation energy to methyl jumps as 8.3 ± 1.3 kJ/mol. It is proposed that this energetic barrier may be a useful probe of changes in the electronic character of the Co-C bond that accompany the biological role of this molecule in such enzymes as methionine synthase.Key words: cobalamin, solid-state NMR, deuterium NMR, molecular dynamics.

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