Isamu Ono

Ab initio calculations of the charge densities in tricarbonyl(boat p-xylene)chromium complexes

Abstract Ab initio SCF calculations predict that the charge densities on the aryl carbons of Cr(boat p -xylene)(CO) 3 and also the difference in charge density from the free boat p -xylene are dependent on the degree of deformation of the boat. This prediction is consistent with the observed geometry-dependent 13 C NMR complexation shifts of Cr(paracyclophane)(CO) 3 complexes.

Monte Carlo Simulation on Nematic Order of Chain Model Using Mean Field Potential—Order Parameter in Binary Mixture

Abstract Monte Carlo simulations for the linear chain model composed of four successive atoms have been performed using the method of Vacatello and lovino based on the Flory-Ronca-Irvine mean field theory. We assumed three kinds of molecules having different ordering parameters and calculated each pure system and the binary systems of these molecules. The ordering properties for each component have been determined as a function of temperature and composition. In the binary system consisting of substances exhibiting the nematic phase with different order parameters, there is an approximately linear relationship between the order parameter and the composition. When the isotropic molecules are mixed with the nematic substance, the order parameter decreases with increasing mole fraction of the isotropic molecule, and the nematic phase changes into the isotropic phase at a certain composition.

Structure Effect of Solute on Orientational Order in Binary Mixture by 2H-NMR and Molecular Simulations

Abstract The orientational order parameters of six solutes with different shapes and sizes dissolved in two nematic solvents have been measured as a function of temperature. The parameter, Sxx-Syy is correlated with the molecular geometrical structure, while Szz is affected by not only the geometry but also the anisotropy in the polarizability. The molecular dynamics simulations are carried out using a realistic atom-atom potential for evaluating the ordering properties in the nematic phase. The results provide reasonable values of Szz corresponding to experimental ones for solutes and solvents, and also a prediction of uniaxiality for the nematic phase.

Order Parameter in Binary Mixture by Monte Carlo Simulation Hybridized with Mean Field Approximation

Abstract The order parameters of each component in a binary mixture consisting of substances exhibiting a nematic phase and an isotropic phase have been evaluated by Monte Carlo simulation using the method of Vacatello and Iovino based on the Flory-Ronca-Irvine mean field theory. An induction of ordering for an isotropic solute has been obtained in the nematic phase. The degree of induction is dependent not only on the parameters of the interactive orientational potential but also on the anisotropy of the molecular shape of the isotropic solute.

Computer Simulation on Liquid Crystal Order in Cell with Alignment Surfaces

Abstract Monte Carlo simulation based on the Luckhurst-Romano potential has been performed to evaluate the ordering property of liquid crystals in a cell with aligned surfaces. The transition temperature from the nematic to the isotropic phase is the same as that of the bulk system, but the high ordering state is induced near the surface around the transition. In addition, the direction of ordering can be regulated by the ordered particle on the surface. The effect of the alignment surface on the liquid crystal order in the nematic and isotropic phases is estimated by changing the number of alignment particles on the surface.