Unconventional density dependence of the stochastic dynamics in an organic liquid

Maira-Vidal, A.; González, Miguel A.; Jiménez‐Ruiz, Mónica; Bermejo, Francisco Javier; Price, David L.; Enciso, E.; Saboungi, Marie‐Louise; Fernández-Perea, Ricardo; Cabrillo, C.

doi:10.1103/physreve.70.021501

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…The quasi-elastic scattering contribution of methyl groups as side groups in different organic compounds is for the solid state well understood. However, the corresponding analysis of the QENS spectra of the liquid phase are realized in very different ways. , The substance Q 0 offers the possibility to study methyl group rotation without spurious influence of other hydrogen atoms in the molecules probed by neutrons.…”

Section: Introductionmentioning

confidence: 99%

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Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q₀ Studied by Neutron Scattering

et al. 2009

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We present a quasi-elastic neutron scattering (QENS) study on the methyl group dynamics of ubiquinone Q(0) in the solid and liquid state. For solid ubiquinone Q(0), the dynamics can be described with three Lorentzian functions in the framework of a jump model among three equidistant sites on a circle. According to the known molecular structure of Q(0) in the solid state, this is consistent with three nonequivalent methyl groups in the molecule. From the temperature-dependent analysis of the QENS spectra, the activation energies were determined. The barrier heights could be evaluated from librational bands in the inelastic part of the spectra. The results from neutron spectroscopy are compared to Gaussian 03 calculations leading to an assignment of the activation energies to the different methyl groups in Q(0). The dynamics of Q(0) in the liquid state is evaluated with a scattering function taking into account three different molecular motions. It is demonstrated that the temperature dependence of the long-range diffusion and isotropic rotational diffusion exhibit an Arrhenius-like behavior, whereas the process of methyl group rotation in the liquid phase is virtually free of a barrier.

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Section: Introductionmentioning

confidence: 99%

“…However, the corresponding analysis of the QENS spectra of the liquid phase are realized in very different ways. 7,8 The substance Q 0 offers the possibility to study methyl group rotation without spurious influence of other hydrogen atoms in the molecules probed by neutrons.…”

Section: Introductionmentioning

confidence: 99%

Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q₀ Studied by Neutron Scattering

et al. 2009

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An Optical Brillouin Study of a Re-Entrant Binary Liquid Mixture

Bermejo¹,

Letamendia²

2010

Metastable Systems Under Pressure

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International audienceOptical spectroscopy studies on the system betapicoline-D2O which forms a critical mixture showing a closed-loop phase diagram have been carried out along a large range of temperatures, comprising crossing of the two critical curves which define the closed loop of the coexistence curve. Data pertaining the elastic properties of the mixture either in one or two-phase states for the sound velocity and the sound absorption were obtained by means of analysis of the spectra of scattered radiation using Brillouin light scattering spectroscopy

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Quasielastic and inelastic neutron scattering study of methyl group rotation in solid and liquid pentafluoroanisole and pentafluorotoluene

Smuda

Gemmecker

Unruh

2008

The Journal of Chemical Physics

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The rotational motion of the methyl group in pentafluoroanisole (PFA) and in pentafluorotoluene (PFT), respectively, was investigated by quasielastic neutron scattering (QENS). For solid PFA, the rotation can be described by a model for uniaxial rotational jumps between three equidistant sites on a circle. Similar to the molecular structure of alpha-toluene, two nonequivalent methyl groups in the unit cell with two different rotational barriers were found for solid PFT. From the analysis of the quasielastic scattering, the activation energies were determined. The barrier heights could be evaluated from bands in the inelastic part of the spectra. The methyl group dynamics in the liquid state is evaluated for both substances using different scattering functions, which are discussed. An empirical model for the description of the contribution of methyl groups in liquids of small organic molecules to the QENS spectra is presented. It is demonstrated that the process of methyl group rotation in the liquid phase is nearly free of a barrier.

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Unconventional density dependence of the stochastic dynamics in an organic liquid

Cited by 3 publications

References 30 publications

Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q₀ Studied by Neutron Scattering

Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q₀ Studied by Neutron Scattering

An Optical Brillouin Study of a Re-Entrant Binary Liquid Mixture

Quasielastic and inelastic neutron scattering study of methyl group rotation in solid and liquid pentafluoroanisole and pentafluorotoluene

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Unconventional density dependence of the stochastic dynamics in an organic liquid

Cited by 3 publications

References 30 publications

Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q0 Studied by Neutron Scattering

Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q0 Studied by Neutron Scattering

An Optical Brillouin Study of a Re-Entrant Binary Liquid Mixture

Quasielastic and inelastic neutron scattering study of methyl group rotation in solid and liquid pentafluoroanisole and pentafluorotoluene

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Product

Resources

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Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q₀ Studied by Neutron Scattering

Methyl Group Dynamics in Polycrystalline and Liquid Ubiquinone Q₀ Studied by Neutron Scattering