Molecular dynamics simulation of a liquid crystalline mixture

We present results from a molecular dynamics simulation of benzene dissolved in the mesogen 4-n-pentyl-4'-cyanobiphenyl (5CB). The computer simulation is based on a realistic atom-atom potential and is performed in the nematic phase. Singlet orientational distribution functions are reconstructed from order parameters employing several methods, and the estimated distributions are compared with those obtained directly from the trajectory. Transport properties have been studied by calculating translational diffusion coefficients in directions both parallel and perpendicular to the liquid crystalline director. The simulated diffusion coefficients were found to be of the same order of magnitude as those measured in experiments. Second rank orientational time correlation functions are used to investigate molecular reorientations and significant deviations from the small step rotational diffusion model are established. Molecular structure and internal dynamics of 5CB have been examined by correlating the time dependence of dihedral angles with effective torsional potentials. (C) 1997 American Institute of Physics.