X-ray study of the smectic A—nematic phase transition in 4-n-pentylphenyl-4-(trans-4′-n-pentylcyclohexyl) benzoate

X-ray critical scattering from C29H40O2 near the smectiA—nematic phase transition are investigated. The critical exponents γ, ν| and ν⊥ are extracted from the data. The ratio of the longitudinal to the transverse correlation lengths ξ|/ξ⊥, increases gradually with decreasing reduced temperature t = (T – Tc)/Tc, for 4 × 10−4 ≦ t ≦ 10−3.