Neutron Diffraction as a Tool to Explore the Free Energy Landscape in Orientationally Disordered Phases

Rovira-Esteva, M.; Pardo, Luis Carlos; Tamarit, J. Ll.; Bermejo, F. J.

doi:10.1007/978-90-481-3408-3_5

Cited by 2 publications

(4 citation statements)

References 21 publications

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“…Both the plastic and the glassy crystalline phases of F-113 display a bcc structure, as was also previously reported for F-112. 19 Figure 2(a) shows a few of the diffractograms obtained for F-113 and F-112, where the shift in the position of the diffraction peaks with temperature is clearly apparent. Fits to these neutron scattering measurements allow to obtain the characteristic parameters of the sample structure.…”

Section: Resultsmentioning

confidence: 99%

“…[14][15][16][17][18][19] Halogen-ethane derivatives have been thoroughly characterized macroscopically (heat capacity, thermodynamic magnitudes, phase transitions, etc.) and microscopically (molecular dynamics, crystallographic structure, relaxation dynamics, molecular structure, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…seeking to find a relation between its physical properties and its intermolecular interactions, as well as its intramolecular features, which can influence both the short-and the long-range order. [14][15][16][17][18][19][20][21][22] F-112 and F-113 are archetypal examples in which a mixture of conformers is present, and for which a complicated sequence of calorimetric transitions appears. Figure 1 shows the two F-112 conformers, gauche and trans, and the two F-113 conformers, C 1 and C s .…”

Section: Introductionmentioning

confidence: 99%

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Thermal properties of halogen-ethane glassy crystals: Effects of orientational disorder and the role of internal molecular degrees of freedom

Vdovichenko

Кривчиков

Korolyuk

et al. 2015

The Journal of Chemical Physics

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The thermal conductivity, specific heat, and specific volume of the orientational glass former 1,1,2-trichloro-1,2,2-trifluoroethane (CCl 2 F-CClF 2 , F-113) have been measured under equilibrium pressure within the low-temperature range, showing thermodynamic anomalies at ca. 120, 72, and 20 K. The results are discussed together with those pertaining to the structurally related 1,1,2,2-tetrachloro-1,2-difluoroethane (CCl 2 F-CCl 2 F, F-112), which also shows anomalies at 130, 90, and 60 K. The rich phase behavior of these compounds can be accounted for by the interplay between several of their degrees of freedom. The arrest of the degrees of freedom corresponding to the internal molecular rotation, responsible for the existence of two energetically distinct isomers, and the overall molecular orientation, source of the characteristic orientational disorder of plastic phases, can explain the anomalies at higher and intermediate temperatures, respectively. The soft-potential model has been used as the framework to describe the thermal properties at low temperatures. We show that the low-temperature anomaly of the compounds corresponds to a secondary relaxation, which can be associated with the appearance of Umklapp processes, i.e., anharmonic phononphonon scattering, that dominate thermal transport in that temperature range. C 2015 AIP Publishing LLC. [http://dx

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal properties of halogen-ethane glassy crystals: Effects of orientational disorder and the role of internal molecular degrees of freedom

Vdovichenko

Кривчиков

Korolyuk

et al. 2015

The Journal of Chemical Physics

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“…26 Nevertheless, studies of the structure at the inter-and intramolecular scale showed that the interplay of features at these two different length scales may explain the complex dynamics of F-112. [27][28][29] The present work is focused on the determination of the intramolecular structure of F-112, its interplay with intermolecular ordering in the liquid phase, and a deep analysis of the short-range order, and is organized as follows: After a short description of the experimental and simulation procedures, a fit method to obtain molecular parameters from the neutron diffraction data is presented. The intramolecular structure of F-112 will then be obtained from experimental data.…”

Section: Introductionmentioning

confidence: 99%

Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

et al. 2011

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We report on the interplay between the short-range order of molecules in the liquid phase of 1,1,2,2-tetrachloro-1,2-difluoroethane and the possible molecular conformations, trans and gauche. Two complementary approaches have been used to get a comprehensive picture: analysis of neutron-diffraction data by a Bayesian fit algorithm and a molecular dynamics simulation. The results of both show that the population of trans and gauche conformers in the liquid state can only correspond to the gauche conformer being more stable than the trans conformer. Distinct conformer geometries induce distinct molecular short-range orders around them, suggesting that a deep intra-and intermolecular interaction coupling is energetically favoring one of the conformers by reducing the total molecular free energy.

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Neutron Diffraction as a Tool to Explore the Free Energy Landscape in Orientationally Disordered Phases

Cited by 2 publications

References 21 publications

Thermal properties of halogen-ethane glassy crystals: Effects of orientational disorder and the role of internal molecular degrees of freedom

Thermal properties of halogen-ethane glassy crystals: Effects of orientational disorder and the role of internal molecular degrees of freedom

Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

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