title: Reliability of Orientational Order Parameters Determined from Two-dimensional X-ray Diffraction Patterns: A Simulation Study.
abstract: The orientational order parameter S2 is one of the most important quantities to describe the degree of long-range orientational ordering of liquid crystals. There are several approaches to experimentally measure this order parameter of liquid crystalline phases but every method includes substantial simplifications and assumptions. We present a simulation-based approach to elucidate the reliability of the method of Davidson, Petermann and Levelut to measure S2 via 2D X-ray experiments. We have found that this method slightly underestimates S2 by an absolute value of only 0.05 and thus provides reliable measures of S2 by X-ray diffraction.
authors.affiliation: Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Jenz
authors.affiliation: Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Jagiella
authors.affiliation: Department of Physics, 390 UCB, University of Colorado, Boulder, CO, 80309-0390, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Glaser
authors.affiliation: Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Giesselmann
keywords: 2D X-ray diffraction patterns; Gay-Berne potential; MD simulations; liquid crystals; orientational order parameter