Biaxial phases in mineral liquid crystals

Rotational diffusion of biaxial probes in biaxial liquid crystal phases, Mol. Phys., 85, 299-333 (1995)

Molecular model of biaxial ordering in nematic liquid crystals composed of flat molecules with four mesogenic groups.

Relative stability of uniaxial and biaxial nematic phases is analyzed in a model nematic liquid crystal composed of flat molecules of C2h symmetry with four mesogenic groups rigidly linked to the same center. The generalized effective quadrupole mean-field potential is proposed and its constants are evaluated numerically for the pair intermolecular potential based on Gay-Berne interaction betwe...

Temperature-concentration behaviour of the order parameter in the nematic phases of a lyotropic liquid crystal

2014 The temperature variations of the order parameter invariants are measured in the uniaxial and biaxial nematic phases of different mixtures of potassium laurate, 1-decanoL D2O. They show that the uniaxial to biaxial nematic phase transitions are second-order and mean-field, including in the case of the reentrant concentration, which gives the sequence discotic-biaxial-discotic of nematic ph...

Mineralogy, Raman spectroscopy and lattice parameter characterization of biotite with hexagonal structure from Borujerd hornfels and migmatites

Biotite is a common rock-forming mineral and accepts a variety of elements in its structure. The valuable information of crystallization conditions of the biotite mineral obtain on natural biotite composition. The biotite mineral is one of the main mineral phases of pelitic rocks which are formed in a wide range of geological conditions. In this research, microscopic mineralogy, Raman spectrosc...

Biaxial Order Parameters in Liquid-Crystals - Their Meaning and Determination With Nuclear-Quadrupole Resonance

A simple formulation is presented for the analysis of nuclear quadrupole spectra in biaxial liquid crystals based on orientational order parameters. The analysis contains no tilt angle or other model-dependent parameters not directly measured in NMR experiments. The observability and effect of various order parameters on the asymmetry of the electric field gradient q is discussed. It is shown t...