Molecular dynamics simulations of liquid crystal systems will be carried out using atomistic potentials to model detailed molecular structure. Two basic models will be used. In model 1, molecules will be represented by Lennard-Jones 12:6 atoms. In model 2, molecules will be composed of Gay-Berne particles and Lennard-Jones sites. Both models will use data from large scale density functional theory calculations to determine intramolecular potentials. Model 1 will be used to determine accurate data for structural and dynamical properties for molecules in nematic liquid crystals, and provide the first accurate predictions for rotational viscosities of a realistic representation of a nematic phase. Model 2 will be used to carry out simulations of macromolecular liquid crystals and study molecular organisation in these systems. Simulations of a chiral dopant molecule in a Gay-Berne solvent will also be carried out. These calculations will be used to provide reliable predictions for helical twisting power of chiral dopants. Together with other techiniques, these calculations will be used to provide insights into the phenomenon of temperature-induced twist inversion.