Prediction of Optical and Dielectric Properties of 4-Cyano-4-pentylbiphenyl Liquid Crystals by Molecular Dynamics Simulation, Coarse-Grained Dynamics Simulation, and Density Functional Theory Calculation

Abstract

The Maier–Meier theory and Vuks theory were used to obtain the dielectric anisotropy and birefringence of the 4-cyano-4-pentylbiphenyl (5CB) liquid crystal system for a benchmark. The molecular dynamics (MD) simulation, coarse-grained molecular dynamics (CGMD) simulation, and the density functional theory (DFT) calculation were used to get the required parameters of the Maier–Meier theory and Vuks theory. The molecular density obtained by the MD simulation is about 1.05 g/cm3, which is very close to the available experimental value of 1.008 g/cm3. In the CGMD simulation, the order parameter is about 0.44 for the 5CB conformation at the temperature that the transformation from the nematic to disorder arrangement occurs. The polarizability (α), polarizability anisotropy (Δα), and dipole moment (μ) of a 5CB molecule were obtained by the DFT calculation with the functional of B3LYP/6-31+G(2d,p). With these parameters, the birefringence of 5CB by the Vuks theory is very close to the experimental value with the...