Structure and elasticity of nematic and isotropic liquid crystals

Nguyen HP. Structure and elasticity of nematic and isotropic liquid crystals. Bielefeld (Germany): Bielefeld University; 2002.In this thesis, we address four problems: (1) Computer simulation of a model for isotropic liquids and nematic liquid crystals consisting of soft-ellipsoidal particles. (2) The correlation functions in the bulk of the simulated systems. (3) The elastic properties in the bulk of the nematic phases. (4) Structures of isotropic liquids near walls. We model the nematic liquid crystals molecules as soft-ellipsoidal particles interacting through repulsive forces. Monte Carlo and molecular dynamics methods are employed to simulate the isotropic phases and the nematic phases. We study the following correlation functions: the one-particle distribution function, the two-particle distribution function, the total correlation function and the direct correlation function. These functions are determined without any approximation. The elastic constants of the simulated nematic phases are computed from the direct correlation function via the Poniewierski-Stecki's theory. The density-orientation profile of the confined system in the isotropic phase is studied by using the direct correlation function with the density functional theory