UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 18:32
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Conference: Bucharest University Faculty of Physics 2014 Meeting


Section: Polymer Physics


Title:
Using the Lebwohl-Lasher Model in Computer Simulation of the Nematic Liquid Crystals


Authors:
M. MOISESCU, E. BARNA, V. BARNA, C. BERLIC, B. MANOLESCU


Affiliation:
University of Bucharest, Faculty of Physics, 405 Atomistilor, Magurele-Ilfov, 077125, Romania


E-mail
marius@unibuc.ro


Keywords:
nematic liquid crystals, Monte Carlo simulations, Lebwhol Lasher model, topological defects


Abstract:
In the present work, we present the use of the computer simulation in investigation of the challenging phenomena regarding the physical behavior of the liquid crystals, difficult to reach by experiments or by theory.We have a practical approach, showing the essential sections of the source code of the Monte Carlo technique, with emphasis on the Lebwhol Lasher model.Consequently, we show the methods used to simulate a cubic lattice occupied by liquid crystal molecules having a pair potential and using a computational algorithm based on repeated representative random sampling. In order to predict the evolution of a very complex system, we may consider various factors that may influence the behavior of a liquid crystal such as surface properties, disturbances induces by confined geometries, size, position and number of the inclusions, temperature, electric or magnetic field, or dielectric anisotropy of molecules.According with the chosen interaction potential, we consider molecules as unit vectors described by their Cartesian components, free to rotate and interact with each other through an orientation dependent energy. The motion, the interaction and the evolution of the molecules follow the rules of Monte Carlo simulations and Lebwhol Lasher model. We also made correlations between the theoretical results, our source code and its outcome, showing how we can establish the local direction of the nematic director and topological defects, essential conditions to build liquid crystals based devices.As a final result, our work makes possible to understand how to conduct an effective abd efficient Monte Carlo simulation of nematic liquid crystals.