X-ray study of the hexatic-B to smectic-A phase transition in liquid crystal films.

Rotating-anode x-ray measurements on thick, free-standing films of the liquid crystal compound n-butyl 4'-n-hexyloxybiphenyl- 4-carboxylate (46OBC) were used to probe the critical behavior at the three-dimensional hexatic-B to smectic-A phase transition. The position and width of the scattering peaks exhibited (1- alpha) singularities in agreement with theory and heat capacity results.