Monte Carlo simulations of zero electric field gradient liquid crystal mixtures

We explore with Monte Carlo simulations the NMR finding that solutes in spe cial nematic liquid crystal mixtures 'feel' zero average electric held grad ient F-ZZ. The simulations involve solute-solvent mixtures of 1000 identica l Gay-Berne ellipsoidal particles with added electric quadrupoles of varyin g strengths placed at particle centres. As long as all quadrupoles are suff iciently small, F-ZZ calculated at the particle centres is equal for all pa rticles. For larger quadrupole moments, interactions among quadrupoles alte r the interparticle distribution and subsequently F-ZZ depends on both solv ent and solute quadrupoles; in general, the quadrupolar interactions produc e a negative contribution to energy. (C) 2000 Elsevier Science B.V. All rig hts reserved.