Light-Scattering Study of the Nematic Twist Constant near the Smectic-<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi></math></span> Transition

R. Mahmood; D. Brisbin; I. Khan; C. Gooden; A. Baldwin; D. L. Johnson; M. E. Neubert

doi:10.1103/PhysRevLett.54.1031

Light-Scattering Study of the Nematic Twist Constant near the Smectic- $A$ Transition

R. Mahmood, D. Brisbin, I. Khan, C. Gooden, A. Baldwin, D. L. Johnson, and M. E. Neubert

Phys. Rev. Lett. 54, 1031 – Published 11 March 1985

Abstract

We report the first high-resolution study of the nematic twist coefficient, $K_{2}$ , above the smectic- $A$ transition. The twist coefficient exponent, $ρ_{2}$ , is in reasonable agreement with x-ray studies of smectic- $A$ correlation length exponents, i.e., $ρ_{2} \sim 2 ν_{⊥}^{x} - ν_{∥}^{x}$ , and in good agreement with the smectic dilation coefficient exponent, $φ$ . $ρ_{2}$ is less than the $x - y$ value and is nonuniversal.