Molecular properties of a bent-core nematic liquid crystal A131 by multi-level theory simulations |
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Authors: | Jingwei Liu Rongfeng Guan Xuanchen Dong |
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Affiliation: | 1. Jilin Provincial Key Laboratory for Numerical Simulation, Jilin Normal University, Siping, People’s Republic of China;2. College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang, People’s Republic of China;3. College of Chemistry, Jilin University, Changchun, People’s Republic of China |
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Abstract: | ABSTRACTMulti-level theory simulations have been performed to model a number of important molecular properties of a bent-core nematic liquid crystal (LC) A131. These important properties include molecular conformations, molecular Raman spectra, differential polarisability ratios, molecular crystals packing, atomic LC structures, order parameters, and Raman depolarisation spectra. The simulations contain four theory levels, involving molecular quantum chemistry, molecular crystal packing, super cell density functional based tight binding optimisation, and super cell molecular dynamics calculations. To heat initial optimised super cell structures, molecular dynamics simulations reveal phase transitions to uniaxial and biaxial nematic phases from molecular crystals. LC atomic structures result in direct calculations on order parameters, which can be further applied to computations on Raman depolarisation spectra with differential polarisability ratios, obtained in the molecular quantum chemistry theory level. The good agreement of simulated Raman depolarisation spectra with the experiment provides a detailed analysis on the unusually low values of experimental uniaxial order parameters. |
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Keywords: | Liquid crystal biaxial nematic phases Raman depolarisation spectra multi-level theory simulations |
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