Abstract
High-resolution ac calorimetric, x-ray, and light-scattering measurements have been made on (4O.7) near the nematic-smectic- phase transition. This transition is second order, with a variation in which is well described by a critical exponent corresponding to the three-dimensional model. The longitudinal and transverse correlation lengths exhibit single-power-law divergences over the reduced-temperature range to 3× with exponents and , respectively. The anisotropic hyperscaling relation is satisfied to within the errors. A dynamical-scaling analysis of light-scattering measurements of the bend-mode director fluctuations with elastic constant yields values for which agree absolutely with the x-ray measurements. Thus the data are all internally consistent, and they appear to exclude all current theories of the nematic-smectic- transition. It is observed that the overall critical behavior in smectic liquid crystals is sensitive to the width of the nematic range; this may offer an explanation for the apparent nonuniversality of the exponents.
- Received 10 January 1983
DOI:https://doi.org/10.1103/PhysRevA.27.3234
©1983 American Physical Society