Rotational dynamics of a dipolar supercooled liquid

Sesé, G.; Urbina, Jordi Ortiz de; Palomar, Ricardo

doi:10.1063/1.4752426

Cited by 9 publications

(12 citation statements)

References 24 publications

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“…, as commonly observed in the relaxation spectra of supercooled molecular liquids and glasses [25,26]. The characteristic relaxation time increases nearly exponentially with salt concentration, while the stretching parameter β decreases from 0.7 to around 0.3 [ Fig.…”

mentioning

confidence: 64%

Orientationally Glassy Crystals of Janus Spheres

et al. 2014

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Colloidal Janus spheres in water (one hemisphere attractive and the other repulsive) assemble into two-dimensional hexagonal crystals with orientational order controlled by anisotropic interactions. We exploit the decoupled translational and rotational order to quantify the orientational dynamics. Via imaging experiments and Monte Carlo simulations we demonstrate that the correlations in the orientation of individual Janus spheres exhibit glass-like dynamics that can be controlled via the ionic strength. Thus, these colloidal building blocks provide a particularly suitable model glass system for elucidating non-trivial dynamics arising from directional interactions, not captured by the consideration of just translational order.

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mentioning

confidence: 64%

Orientationally Glassy Crystals of Janus Spheres

et al. 2014

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“…16) But the quantity (L/2) ψ is the arc length moved by any one end of a diatomic molecule rotating through an angle of ψ. So, the total kinematic length is just a root-mean-square combination of center-of-mass displacements and arc lengths traversed for our molecules.…”

Section: Geodesic Paths Taken By a Liquid Of Linear Molecules: Pamentioning

confidence: 99%

“…9,10 Another inspiration stems from the existence of quantitative and even qualitative differences in character between rotational and translational motion in supercooled liquids. [11][12][13][14][15][16] But the central question for us is the same as it is for the atomic cases: what is the role of the overall connectivity of the potential energy surface in establishing a liquid's dynamical preferences?…”

Section: Introductionmentioning

confidence: 98%

The inherent dynamics of a molecular liquid: Geodesic pathways through the potential energy landscape of a liquid of linear molecules

Jacobson

Stratt

2014

The Journal of Chemical Physics

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Because the geodesic pathways that a liquid follows through its potential energy landscape govern its slow, diffusive motion, we suggest that these pathways are logical candidates for the title of a liquid's “inherent dynamics.” Like their namesake “inherent structures,” these objects are simply features of the system's potential energy surface and thus provide views of the system's structural evolution unobstructed by thermal kinetic energy. This paper shows how these geodesic pathways can be computed for a liquid of linear molecules, allowing us to see precisely how such molecular liquids mix rotational and translational degrees of freedom into their dynamics. The ratio of translational to rotational components of the geodesic path lengths, for example, is significantly larger than would be expected on equipartition grounds, with a value that scales with the molecular aspect ratio. These and other features of the geodesics are consistent with a picture in which molecular reorientation adiabatically follows translation—molecules largely thread their way through narrow channels available in the potential energy landscape.

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“…Production runs of 1 ns at the highest temperature and of 6 ns at the lowest temperature have been performed in the (N,V,T) ensemble. Computed glass transition temperature for MeO is 95 K [17].…”

Section: Models and Methodologymentioning

confidence: 99%

“…It should be noted that 99% of methanol molecules are hydrogen bonded at room temperature [13]. The role of HB on ionic association [14], single particle dynamics [15,16,17] and thermodynamic properties [18] was previously investigated for this system. On the other hand, the influence of temperature on the dielectric properties of the non-associated liquid at very low temperatures will also be studied.…”

Section: Introductionmentioning

confidence: 99%

Influence of hydrogen bonds and temperature on dielectric properties

Urbina

Sesé

2016

Phys. Rev. E

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Dielectric properties have been evaluated by means of Molecular Dynamics simulations on two model systems made up by dipolar molecules. One of them mimics methanol, whereas the other differs from the former only in the ability of forming hydrogen bonds. Static dielectric properties such as permittivity and the Kirkwood factor have been evaluated, and results have been analyzed by considering the distribution of relative orientations between molecular dipoles. Dipole moment time correlation functions have also been evaluated. The relevance of contributions associated to autocorrelations of molecular dipoles and to cross-correlations between dipoles belonging to different molecules has been investigated. For methanol, the Debye approximation for the overall dipole moment correlation function is not valid at room temperature. The model applies when hydrogen bonds are suppressed, but it fails upon cooling the non-associated liquid. Important differences between relaxation times associated with dipole auto and cross-correlations as well as their relative relevance are at the root of the Debye model breakdown. *

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Rotational dynamics of a dipolar supercooled liquid

Cited by 9 publications

References 24 publications

Orientationally Glassy Crystals of Janus Spheres

Orientationally Glassy Crystals of Janus Spheres

The inherent dynamics of a molecular liquid: Geodesic pathways through the potential energy landscape of a liquid of linear molecules

Influence of hydrogen bonds and temperature on dielectric properties

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