Nuclear Quadrupole Coupling Constants

Lücken, E. A. C.

doi:10.1016/b978-0-12-401104-5.50009-2

Cited by 214 publications

(353 citation statements)

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“…The sign of the quadrupole term has been chosen to have ! q > 0 for 14 N in ammonia [23]. Axial symmetry of the eld gradient about an axis which makes an angle with respect to the static eld was assumed [22].…”

Section: The Nitrogen Resonance Signalmentioning

confidence: 99%

Measurement of proton and nitrogen polarization in ammonia and a test of equal spin temperature

Adeva¹,

Arık²,

Arvidson³

et al. 1998

Nuclear Instruments and Methods in Physics Research Section A:

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The 1996 data taking of the SMC experiment used polarized protons to measure the spin dependent structure function g 1 of the proton. Three liters of solid granular ammonia were irradiated at the Bonn electron linac in order to create the paramagnetic radicals which are needed for polarizing the protons. Proton polarizations of (90 2:5) % were routinely reached. An analysis based on a theoretical line-shape for spin-1 systems with large quadrupolar broadening was developed which allowed the nitrogen polarization in the ammonia to be determined with a 10 % relative error. The measured quadrupolar coupling constant of 14 N agrees well with earlier extrapolated values. The polarization of the nitrogen nuclei was measured as a function of the proton polarization in order to provide a test of the equal spin temperature (EST) hypothesis. It was found to be closely valid under the dynamic nuclear polarization conditions with which the protons are polarized. Large deviations from EST could be induced by cross relaxing the proton and nitrogen spin systems at low elds. Nitrogen polarizations up to 40% were reached by these means.

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Section: The Nitrogen Resonance Signalmentioning

confidence: 99%

Measurement of proton and nitrogen polarization in ammonia and a test of equal spin temperature

Adeva¹,

Arık²,

Arvidson³

et al. 1998

Nuclear Instruments and Methods in Physics Research Section A:

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“…Appropriate developments in instrumentation, for example the setup allowing radiolysis and EPR measurements at variable temperature, permitted the identification of the various reaction intermediates and, occasionally to discover changes in their conformation. This was the case with single crystals of Ph 3 M(CO) 5 (with M = Mo, W), which were shown to trap, after radiolysis, the electron excess species (Ph 3 M(CO) 4 ) -, the electron deficient species Ph 3 M(CO) 5 + and the phosphinyl radical coordinated to the metal centre, Ph 2 P . ..M(CO) 5 (Fig.…”

Section: Magnetic Resonance Spectroscopymentioning

confidence: 97%

“…This was the case with single crystals of Ph 3 M(CO) 5 (with M = Mo, W), which were shown to trap, after radiolysis, the electron excess species (Ph 3 M(CO) 4 ) -, the electron deficient species Ph 3 M(CO) 5 + and the phosphinyl radical coordinated to the metal centre, Ph 2 P . ..M(CO) 5 (Fig. 6).…”

Section: Magnetic Resonance Spectroscopymentioning

confidence: 97%

“…He used the Nuclear Quadrupole Resonance (NQR) technique to study the electronic structure of diamagnetic crystalline molecular solids. [5] He was thus able to provide a precise description of the chemical bonds by measuring the quadrupole coupling constant of the quadrupolar nuclei 35/37 Cl, 79/81 Br, 63/65 Cu, 75 As and 121/123 Sb. He considerably improved the performance of this technique through the construction of a pulsed spectrometer and the development of specific instrumentation for the study of large single crystals.…”

Section: Magnetic Resonance Spectroscopymentioning

confidence: 99%

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Physical Chemistry at the University of Geneva

Hagemann

Wesołowski²,

Berclaz³

et al. 2009

Chimia

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“…For EFG calculations, the formal derivative parameter would be a point quadrupole at some position; usually the EFG is evaluated at the position of a quadrupolar nucleus [34,35]. For EPR calculations, the derivative parameter would be the component of an external magnetic field or a nuclear spin or the nuclear spin magnetic moment [36,37].…”

Section: Introduction: Where the Theory Of Relativity And The Quantummentioning

confidence: 99%

Relativistic calculations of magnetic resonance parameters: background and some recent developments

Autschbach

2014

Phil. Trans. R. Soc. A.

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This article outlines some basic concepts of relativistic quantum chemistry and recent developments of relativistic methods for the calculation of the molecular properties that define the basic parameters of magnetic resonance spectroscopic techniques, i.e. nuclear magnetic resonance shielding, indirect nuclear spin-spin coupling and electric field gradients (nuclear quadrupole coupling), as well as with electron paramagnetic resonance g-factors and electron-nucleus hyperfine coupling. Density functional theory (DFT) has been very successful in molecular property calculations, despite a number of problems related to approximations in the functionals. In particular, for heavy-element systems, the large electron count and the need for a relativistic treatment often render the application of correlated wave function ab initio methods impracticable. Selected applications of DFT in relativistic calculation of magnetic resonance parameters are reviewed.

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Nuclear Quadrupole Coupling Constants

Cited by 214 publications

References 0 publications

Measurement of proton and nitrogen polarization in ammonia and a test of equal spin temperature

Measurement of proton and nitrogen polarization in ammonia and a test of equal spin temperature

Physical Chemistry at the University of Geneva

Relativistic calculations of magnetic resonance parameters: background and some recent developments

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