Simulations using hard particles

Abstract

A short review is given of recent progress in the computer simulation of liquid crystal phases using hard particles. Emphasis is placed on the richness of phase behaviour that may result from the effects of molecular size and shape alone, and on the role of simulations in testing modern theories of liquid crystal phase transitions, structure and dynamics. Two specific examples are treated in detail: the simulation of twisted nematic liquid crystals, allowing a direct calculation of the twist elastic constant and the helical twisting power of chiral dopant molecules; and the recent quantitative explanation of diffusive behaviour in isotropic and nematic liquids using kinetic theory.

Exact constructions of a family of dense periodic packings of tetrahedra

“…In the last decade, scientific attention has broadened from the study of dense packings of spheres (the simplest shape that does not tile Euclidean space) [5][6][7][8][9][10][11][12][13][14] to dense packings of disordered [15][16][17][18][19] and ordered [20][21][22] nonspherical particles. In addition, the equilibrium phase behavior and transport properties of hard nonspherical particles have been of topics of great interest [23][24][25][26]. Nonsphericity introduces rotational degrees of freedom not present in sphere packings, and can dramatically alter the characteristics from those of sphere packings.…”

The phase behavior of linear and partially flexible hard-sphere chain fluids and the solubility of hard spheres in hard-sphere chain fluids

“…This was first predicted theoretically by Onsager 8 and observed later in molecular simulation studies of hard disks, 9, 10 hard ellipsoids, [11][12][13][14] hard spherocylinders, [15][16][17][18][19][20] and cut hard spheres. 21 Frenkel, 22 Allen, 23 Care and Cleaver, 24 and Wilson 25 provided excellent reviews on the molecular simulation of liquid crystals.…”

Liquid-crystal phase equilibria of Lennard-Jones chains

“…Simulations based on coarse-grained models can access longer time and length scales than their atomistic counterparts, allowing a bulk description of fluids. Coarse-grained models are commonly used to represent a simplified picture of large molecules, such as biomolecules [12][13][14][15][16], polymers [17][18][19][20][21][22], or liquid crystals [23][24][25][26][27][28]. Moreover, simulation results obtained from coarse-grained models can be directly compared with theoretical predictions that are based on a well-defined Hamiltonian, such as the family of perturbation theories developed from the statistical association fluid theory (SAFT) [29][30][31][32][33][34][35][36].…”