Reorientations dans les cristaux moleculaires et fonctions de correlation

Rigny, Paul

doi:10.1016/0031-8914(72)90099-7

Cited by 68 publications

(26 citation statements)

References 3 publications

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“…Though applicable for both models, symmetry plays an important role in simplifying the calculations for the symmetry related jumps model, and we may follow their arguments, based on Rigny [19], for the present work.…”

Section: Symmetry Arguments In Lineshape Calculationsmentioning

confidence: 93%

NMR study of molecular reorientation under fivefold symmetry - solid permethylferrocene

Wemmer¹,

Ruben²,

Pines³

1981

J. Am. Chem. Soc.

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The ring reorientation in permethylferrocene has been studied using high resolution solid state 13 c NMR. The constraints which symmetry places upon the number and types of motional parameters which may be determined from the NMR spectrum are discussed. From comparison of the experimental lineshapes in the slow reorientation temperatures range with theoretical models for random rotations and symmetry related jumps, it is concluded that the reorientation occurs as jumps between symmetry related orientations with jumps of 2-n/5 highly favored over 4rr/5. The activation energy derived for the jump process is 13.5 kjoules/mole.

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Section: Symmetry Arguments In Lineshape Calculationsmentioning

confidence: 93%

NMR study of molecular reorientation under fivefold symmetry - solid permethylferrocene

Wemmer¹,

Ruben²,

Pines³

1981

J. Am. Chem. Soc.

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“…With identically oriented NH / 4 ions, the lattice is in its ordered state (Fig. 1b) relaxation times exists in the theories (8)(9)(10)(11) and no anisotropy follows from (7,25,26) at all temperatures.…”

Section: Functionmentioning

confidence: 98%

“…a 2nd rank symmetric tensor in the cubic lattice (27). We Further, by using the condition t ӷ 1/v 0 and the identity recall that according to the theories developed in (8)(9)(10)(11) …”

Section: Functionmentioning

confidence: 99%

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Proton Spin–Lattice Relaxation in Monocrystalline Ammonium Chloride

Bashirov

1996

Journal of Magnetic Resonance, Series A

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“…It is well known that in such a case group-theoretical methods can be used to calculate arbitrary correlation functions. 39 Below we focus on the results of such a calculation and for details we refer to Ref. 34. In the Experimental section it was found that 12 magnetically inequivalent sites are available for each deuteron.…”

Section: Stochastic Jump Modelsmentioning

confidence: 99%

Rotational motion in the molecular crystals meta- and ortho-carborane studied by deuteron nuclear magnetic resonance

Winterlich

Böhmer

Diezemann

et al. 2005

The Journal of Chemical Physics

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Spin-lattice and spin-spin-relaxation times, one- and two-dimensional spectra as well as two- and four-time correlation functions were measured for the molecular crystals ortho- and meta-carborane using deuteron nuclear magnetic resonance. It is found that in their noncubic phases these crystals exhibit highly anisotropic motions. In order to allow for a quantitative description of the motional geometry of the carboranes several stochastic models are formulated. By comparison of the model calculations with the experimental results it is found that the dynamics of these quasi-icosahedrally shaped molecules is governed by a composite reorientation process. Here the molecules perform threefold jumps around a molecule-fixed axis which itself can be tilted in four different directions with respect to a crystal-fixed axis. The tilt angle increases significantly with increasing temperature. On the basis of measurements of four-time stimulated-echo functions, implications for dynamic heterogeneity also in comparison with that of supercooled liquids are discussed.

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Reorientations dans les cristaux moleculaires et fonctions de correlation

Cited by 68 publications

References 3 publications

NMR study of molecular reorientation under fivefold symmetry - solid permethylferrocene

NMR study of molecular reorientation under fivefold symmetry - solid permethylferrocene

Proton Spin–Lattice Relaxation in Monocrystalline Ammonium Chloride

Rotational motion in the molecular crystals meta- and ortho-carborane studied by deuteron nuclear magnetic resonance

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