Hard Nonspherical Particles Research Articles

Computer simulation of a twisted nematic liquid crystal

We have performed the first computer simulation of a twisted nematic liquid crystal using non-spherical hard particles in modified periodic boundary conditions. The director profiles are stable, suggesting that the technique may usefully complement conventional simulations of unperturbed liquid crystals. We make preliminary calculations of the twist elastic constant K 2 by measurement of intermolecular torques: the results are in moderately good agreement with those obtained from fluctuation expressions.

On the Landau bicritical point for hard biaxial particles

Abstract We consider the isotropic symmetry breaking bifurcations for an arbitrary free energy functional describing hard non-spherical particles. It is shown that a large class of functionals for hard biaxial particle fluids that incorporate excluded volume effects solely through the distribution averaged pair excluded volume all have Landau bicritical points at the same particle shape parameters.

Erratum: The solution of the hypernetted chain and Percus–Yevick approximations for fluids of hard nonspherical particles. Results for hard ellipsoids of revolution [J. Chem. Phys. 8 7, 1295 (1987)

Erratum: The solution of the hypernetted chain and Percus–Yevick approximations for fluids of hard nonspherical particles. Results for hard ellipsoids of revolution [J. Chem. Phys. <b>8</b> <b>7</b>, 1295 (1987)

The solution of the hypernetted chain and Percus–Yevick approximations for fluids of hard nonspherical particles. Results for hard ellipsoids of revolution

In this paper we describe a general approach which allows the hypernetted chain (HNC) and Percus–Yevick (PY) integral equation theories to be solved numerically for fluids of hard nonspherical particles. Explicit results are given for fluids of hard ellipsoids of revolution and comparisons are made with recent Monte Carlo calculations. It is found that for dense systems of highly anisotropic ellipsoids the HNC and PY closures give significantly different results. The HNC theory is superior predicting the existance of a nematic phase in qualitative agreement with computer simulations. The PY approximation strongly and erroneously suggests that the isotropic phase is stable throughout the liquid regime.

The scaled particle theory for particles of arbitrary shape

The scaled particle theory of Reiss et al. has been extended to hard non-spherical particles and equations analogous to the Percus-Yevick equation have been obtained for mixtures of particles of the same shape but different sizes. The resulting equation of state produces exact second and third virial coefficients which are functions of the average radius, the surface area and the volume of the particle. The equations of state for several systems of hard non-spherical particles are compared with that for a system of hard spheres.