Molecular Fluids and Liquid Crystals in Convex-Body Coordinate Systems

Singh, G. S.; Kumar, Brijesh

doi:10.1006/aphy.2001.6166

Cited by 15 publications

(14 citation statements)

References 91 publications

(51 reference statements)

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“…When going from spheres to nonspherical particles, nontrivial phenomena arise, due to the interplay between translational and rotational degrees of freedom. The slowing down of the dynamics can indeed appear in both translational and rotational properties or in just one of the two.Hard ellipsoids (HE) of revolution [1,8] are one of the most prominent systems composed by hard-body anisotropic particles. HE are characterized by the aspect ratio X 0 a=b (where a is the length of the revolution axis, b is the length of the two other axes) and by the packing fraction X 0 b 3 N=6V, where N is the number of particles and V is the volume.…”

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confidence: 99%

Dynamics of Uniaxial Hard Ellipsoids

2007

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We study the dynamics of monodisperse hard ellipsoids via a new event-driven molecular dynamics algorithm as a function of volume fraction phi and aspect ratio X0. We evaluate the translational D(trans) and the rotational D(rot) diffusion coefficients and the associated isodiffusivity lines in the phi-X0 plane. We observe a decoupling of the translational and rotational dynamics which generates an almost perpendicular crossing of the D(trans) and D(rot) isodiffusivity lines. While the self-intermediate scattering function exhibits stretched relaxation, i.e., glassy dynamics, only for large phi and X(0) approximately 1, the second order orientational correlator C2(t) shows stretching only for large and small X0 values. We discuss these findings in the context of a possible prenematic order driven glass transition.

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confidence: 99%

Dynamics of Uniaxial Hard Ellipsoids

2007

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“…Two technical approaches have been followed to achieve this. The former relies on convex-body coordinate systems [62] and takes biaxial ellipsoids as prototypes for biaxial molecules. The excluded volume between biaxial ellipsoids was first computed by Tijpto--Margo and Evans [63], and then recast in a different form.…”

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confidence: 99%

Statistical Theory of Biaxial Nematic and Cholesteric Phases

Kapanowski

2011

Acta Phys. Pol. A

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A statistical theory of biaxial nematic and cholesteric phases is presented. It is derived in the thermodynamic limit at small density and small distortions. The considered phases are composed of short rigid biaxial or less symmetric molecules. The expressions for various macroscopic parameters involve the one-particle distribution function and the potential energy of two-body short-range interactions. The cholesteric phase is regarded as a distorted form of the nematic phase. Exemplary calculations are shown for several systems of molecules interacting via Corner-type potential based on the Lennard-Jones 12-6 functional dependence. The temperature dependence of the order parameters, the elastic constants, the phase twists, the dielectric susceptibilities, and the flexoelectric coefficients are obtained. The flow properties and defects in nematics are also discussed.

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“…A step forward was moved by Tjipto-Margo and Evans [4] who obtained a closed form for the excluded volume of biaxial ellipsoids which, at variance with Isihara's case, are only endowed with D 2h , instead of D ∞h , symmetry. Both Kihara's and Tjipto-Margo and Evans' computations have been simplified by Singh and Kumar [5], to which the reader is referred for a self-consistent account of convexbody coordinates. Another avenue has been followed by Mulder who computed explicitly the excluded volume for spheroplatelets [6] and spherocuboids [7].…”

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confidence: 99%

Excluded area computations for non-convex molecules

Rosso

2008

Mol. Phys.

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International audienceBy using methods of computer-aided geometric design (CAGD), we compute explicitly the excluded area for a pair of non-convex molecules obtained by moving a disk of radius h on a circular arc of radius R and amplitude 2α: they are referred to as boomerangs or horseshoes, depending on the value of α. As a result, the excluded area always attains its absolute minimum when the molecules are antiparallel, instead of parallel, a feature that makes them a good candidate to study shape polarity effects in steric interactions. Although the excluded area is in general a rather complicated function of the relative orientation, with α and η:=h/R acting as parameters, when η<< 1 a remarkably simple formula is obtained. In this limit, the anisotropic part of the excluded area is independent of η

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Molecular Fluids and Liquid Crystals in Convex-Body Coordinate Systems

Cited by 15 publications

References 91 publications

Dynamics of Uniaxial Hard Ellipsoids

Dynamics of Uniaxial Hard Ellipsoids

Statistical Theory of Biaxial Nematic and Cholesteric Phases

Excluded area computations for non-convex molecules

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