Simulations of some physical parameters of homologous series of nBT and nCHBT at 0.3–20.0 THz

ABSTRACTIn this work, the terahertz (THz) absorption of homologous series of isothiocyanobiphenyls (nBT) and 4-(trans-4ʹ-n-alkylcyclohexyl)isothiocyanato-benzene (nCHBT) are simulated by using the density functional theory (DFT) method. Numerical results show that absorption of the tested nematic liquid crystals (NLCs) varies up to 0.04 in the broad range of 0.3–20.0 THz and takes maximum value in the range of 9–14 THz.In addition, the values of molecular polarisabilities (αo, αe) increase with the increase in the number of carbon atoms in the alkyl chain, while refractive indices (no, ne) decreases. The calculated birefringence (Δn) values for nCHBT are approximately twice as large as the birefringence value for nBT. It is crucial to examine these series of nematic liquid crystals at THz frequencies due to the role of soft matter in various switchable THz components.