Monte Carlo simulations of zero electric field gradient liquid crystal mixtures

We explore with Monte Carlo simulations the NMR finding that solutes in special nematic liquid crystal mixtures 'feel' zero average electric field gradient F-ZZ. The simulations involve solute-solvent mixtures of 1000 identical Gay-Berne ellipsoidal particles with added electric quadrupoles of varying strengths placed at particle centres. As long as all quadrupoles are sufficiently small, F-ZZ calculated at the particle centres is equal for all particles. For larger quadrupole moments, interactions among quadrupoles alter the interparticle distribution and subsequently F-ZZ depends on both solvent and solute quadrupoles; in general, the quadrupolar interactions produce a negative contribution to energy. (C) 2000 Elsevier Science B.V. All rights reserved.