Thermal diffuse x-ray scattering in a model columnar liquid crystal - art.no. 011701

The fluctuation correlation functions and the density-density correlation f unctions for a realistic model of a columnar liquid crystal in its helicall y ordered phase are derived. The influence of positional and orientational molecular fluctuations on the thermal diffuse x-ray scattering is studied w ithin a three-dimensional model of columns inscribed on a triangular lattic e. Resulting from quasi-long-range ordering, very anisotropic long-tail sca ttered intensities are predicted, giving a nonuniversal signature for the h elically ordered columnar liquid crystal phase. Scattered intensities both near the Bragg maxima at the inverse lattice vectors and at the Bragg condi tion due to periodic orientational ordering are treated. The percolation of the long-range behavior for a screw variable composed of two quantities ha ving only quasi-long-range behavior is predicted.