Computer simulation studies of anisotropic systems

Emerson, Andrew; Luckhurst, G. R.; Whatling, S. G.

doi:10.1080/00268979400100094

Cited by 114 publications

(59 citation statements)

References 21 publications

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“…One of these phases is a columnar phase characterized by a nematic ordering of the molecular symmetry axes and a hexagonal arrangement of the columns in the plane perpendicular to the column axes. The same type of phase also occurs in conventional Gay-Berne systems consisting of diskotic particles 53 . Moreover, columnar nematic phases have also been observed in systems of hexabenzocoronene derivatives 14 .…”

Section: A Isotropic Regimementioning

confidence: 74%

Angle-resolved effective potentials for disk-shaped molecules

Heinemann

Pałczynski

Dzubiella

et al. 2014

The Journal of Chemical Physics

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We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van-der-Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.

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Section: A Isotropic Regimementioning

confidence: 74%

Angle-resolved effective potentials for disk-shaped molecules

Heinemann

Pałczynski

Dzubiella

et al. 2014

The Journal of Chemical Physics

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“…13 related to that used by Emerson et al in ref. 10 and based on the dimensions of a triphenylene core, namely : shape anisotropy interaction anisotp e /p s \ 0.345, ropy but using instead energy parameters k \ 1 and e e /e s \ 5, l \ 3 as in refs. 13 and 14. and are used as molecular p s e s units of length and energy.…”

Section: The Model and Its Simulationmentioning

confidence: 99%

Columnar phases and field induced biaxiality of a Gay–Berne discotic liquid crystal

Berardi¹,

Orlandi²,

Zannoni³

2000

Phys. Chem. Chem. Phys.

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We have studied a system of discotic particles with a central transverse dipole using Monte Carlo (MC) computer simulations at constant pressure. We have investigated several temperatures corresponding to nematic and columnar liquid crystal phases and determined the molecular and dipolar organizations. Low temperature columnar phases are characterized by local biaxial ordering of dipoles, even if the system is on the whole uniaxial. However, simulations in the presence of a transverse Ðeld for di †erent Ðeld and dipole strengths show that the system has a large susceptibility and easily becomes biaxial, making it potentially interesting for switching applications. An explicit formulation for the susceptibility in terms of biaxial invariants is derived.

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“…5) [5]. Luckhurst et al have suggested the appearance of a wide, nematic phase, the same as that the calamitic liquid crystal that occurs as a result of calculation of the relationship between the phase structure and the transition point, assuming the discotic liquid crystal is a smooth and rigid plane table using Gay-Berne potential [6].Most of the discotic liquid crystal compounds, however, preferentially show the columnar phase, and few of them form the N D phase (Fig. 6).…”

Section: Hybrid Orientation Of Discotic Liquid Crystalmentioning

confidence: 99%