title: Simple experimental assessment of smectic translational order parameters.
abstract: A procedure to obtain the smectic translational order parameter Sigma from the temperature-dependent intensity I of the fundamental (001) smectic layer peak, observed in small-angle x-ray scattering experiments, is presented. We report results obtained with this procedure on the smectic-A or chiral smectic-A phases of six different liquid crystals, among them a "de Vries"-type 2-{4'-[1'',1''-dihydro-2''-(2''-perfluorobutoxyperfluoroethoxy)- perfluoroethoxy]}phenyl-5'-octylpyrimidine(3M8422) and the antiferroelectric R-4-(1-methylheptyloxycarbonyl)phenyl-4'-octloxybiphenyl-4-carboxylate (MHPOBC) materials. The smectic order parameters obtained are in the range between 0.5 and 0.9. For the "de Vries"-type 3M 8422 we found remarkably high values of Sigma in the order of approximately 0.9.
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
authors.forename: Nadia
authors.initials: N
authors.lastname: Kapernaum
authors.forename: Frank
authors.initials: F
authors.lastname: Giesselmann