Multiple contributions to potentials of mean torque for solutes dissolved in liquid crystal solvents. A comparison of the orientational ordering of anthracene and anthraquinone as solutes in nematic solvents

Dipole-induced ordering in nematic liquid crystals. II. The elusive holy grail

“…From the computer simulation studies it was also concluded that the origin of the discrepancy was most likely the inadequacy of using point quadrupoles for dense systems and an improved description of molecular electrostatic interactions will likely be essential in order to generate solute orientational behavior consistent with that observed experimentally. Nevertheless, these computer simulations can be used to test the accuracy and reliability of theories; the simulations represent an exact system for the theories of Emsley et al 9,28,29 and Photinos et al 10,11,27 The orientational ordering predicted by the Emsley theory was found to be qualitatively consistent with the computer simulations. However, due to the mathematical approximations and the inadequacy of the electrostatic potential, predictions of the long-range contributions to the orientational ordering were not accurate.…”

“…Nevertheless, a study of the solvent-dependence of the orientational behavior of anthracene and anthraquinone, which are molecules with similar shapes and polarizabilities but significantly different quadrupole moments, was undertaken and analyzed using the theory. 29 The distribution of solventsolute intermolecular vectors, and consequently the EFG, was found to be strongly dependent on both solvent and solute molecular properties.…”

“…Emsley, Luckhurst, and coworkers have also discussed the significance of the soluteindependent EFG using a theory for orientational ordering which is closely related to the Maier-Saupe theory of nematics. 9,28,29 In the context of this theory, it was shown that the nematogen quadrupole was the lowest-order multipole that contributed to a nonvanishing EFG. Further, an expression for both the EFG and its contribution to the intermolecular potential was derived.…”

Prediction from Molecular Shape of Solute Orientational Order in Liquid Crystals

“…Although the validity of this approximation for e.g. the electric field gradient has been questioned, ,,− a precise treatment of the problem in which this approximation is avoided is not currently available. Secondly, the fact that the total interaction can be broken down into the sum of long-range and short-range contributions presupposes a separability that in a more detailed picture might not be upheld.…”

Photon upconversion with directed emission

“…Matrixes that are able to orient molecules in space include stretched films and liquid crystals. Anthracene has previously been shown to orient in accordance to its physical aspect ratio when dissolved in a liquid crystalline matrix having a nematic phase 38 39 . Also, anthracene derivatives having intrinsic liquid crystalline properties have been developed 40 41 .…”