Molecular simulation and theory of liquid crystals: chiral parameters, flexoelectric coefficients, and elastic constants

We present an overview of the simulation methods available to calculate the phenomenological coefficients which appear in the Frank free energy of nem atic liquid crystals: the elastic constants, helicity parameter, and flexoe lectric coefficients. We concentrate on approaches which are based on measu ring and correlating molecular orientational stresses, as these have not re ceived much attention previously, and their statistical mechanical basis se ems not to be widely understood. We relate methods which rely on applying e xternal fields or distortions to methods which rely on static equilibrium c orrelations, highlighting some of the unresolved problems, and presenting s ome new results and perspectives.