@article {4944,
	title = {Dipole-induced ordering in nematic liquid crystals. II. The elusive holy grail},
	journal = {Journal of Chemical Physics},
	volume = {113},
	number = {8},
	year = {2000},
	note = {ISI Document Delivery No.: 345AGTimes Cited: 23Cited Reference Count: 47},
	month = {Aug},
	pages = {3452-3465},
	type = {Article},
	abstract = {Similar size and shape molecules with different electric multipoles are used to investigate effects of molecular dipole, quadrupole, and polarizability interactions on the average orientational order of solutes in nematic liquid crystals. Solutes are codissolved in the same sample tube so that the orientational ordering among solutes can be directly compared and analyzed using mean-field models. Permanent dipoles have a negligible influence on solute orientational order. Effects from molecular polarizability interactions could not be separated from short-range interactions. However, order parameters predicted from strong, short-range repulsive forces coupled with interactions between the solute quadrupole and the average electric field gradient felt by the solute are consistent with experimental values. For the nematic mixture 55 wt\% ZLI 1132 in EBBA [N-(pethoxybenzylidene)-p{\textquoteright}-n-butylaniline] the contribution to solute ordering from long-range electrostatic interactions is negligible. (C) 2000 American Institute of Physics. [S0021-9606(00)52232-6].},
	keywords = {AB-INITIO, ELECTRIC-DIPOLE, HARD ELLIPSOIDS, MEAN TORQUE, MOLECULAR QUADRUPOLE-MOMENTS, MONTE-CARLO SIMULATIONS, NMR-SPECTRA, ORDER, ORIENTATIONAL, SOLUTES, SOLVENTS},
	isbn = {0021-9606},
	url = {<Go to ISI>://000088792800063},
	author = {Syvitski, R. T. and Burnell, E. E.}
}
@article {4107,
	title = {Monte Carlo simulations of solute ordering in nematic liquid crystals: Shape anisotropy and quadrupole-quadrupole interactions as orienting mechanisms},
	journal = {Physical Review E},
	volume = {55},
	number = {4},
	year = {1997},
	note = {ISI Document Delivery No.: WV249Times Cited: 17Cited Reference Count: 51},
	month = {Apr},
	pages = {4321-4337},
	type = {Article},
	abstract = {Monte Carlo computer simulations were used to investigate the effects of shape anisotropy and electrostatic interactions as mechanisms for orientational ordering of solutes in nematic liquid crystals. The simulation results were analyzed in terms of two theories of solute ordering which derive mean-field orientational potentials from the intermolecular pair potential. In the calculations, solute and solvent molecular shapes were approximated by hard ellipsoids. Most simulations also incorporated the interaction between point quadrupole moments placed at the centers of the ellipsoids. In the hard-core systems, orientational order parameters and distribution functions were calculated for a collection of different solutes under a variety of conditions. A theory due to Terzis and Photinos [Mol. Phys. 83, 847 (1994)] was found to underestimate the effect of shape anisotropy on orientational ordering drastically. The introduction of an effective solvent packing fraction was unable to improve the predictive power of the theory significantly. The quadrupolar systems were used to investigate a mean-field model for solute ordering which considers an interaction between the solute molecular quadrupole moment with an average electric-field gradient. The simulations indicate that the electric-field gradient sampled by the solute is highly dependent on the properties of the solute, contrary to some experimental evidence. Further, the effects of the intermolecular quadrupolar interactions on orientational ordering and the electric-field gradient were analyzed using a mean-field potential derived here and based on the theory due to Emsley, Palke, and Shilstone [Liq. Cryst. 9, 649 (1991)]. This model was found to provide a qualitatively correct but quantitatively imprecise prediction of orientational ordering.},
	keywords = {acetylene, COMPUTER-SIMULATION, ELECTRIC-DIPOLE INTERACTIONS, HARD ELLIPSOIDS, MEAN TORQUE, MOLECULAR-HYDROGEN, NMR, orientational order, POTENTIALS, SOLVENTS},
	isbn = {1063-651X},
	url = {<Go to ISI>://A1997WV24900067},
	author = {Polson, J. M. and Burnell, E. E.}
}
