Light-scattering studies on the single-layer smecticp-butoxybenzilidenep-octylaniline

An analysis of the intensity of the spectrum of light scattered from the director fluctuations of butoxybenzilidene octylaniline around the nematic to smectic-$A$ transition shows the critical properties of this single-layer material to be wholly analogous to the well-studied bilayer smectics, i.e., the He analogy holds only for the nematic phase while it breaks down for $T<\mathrm{}{T}_c$. The unusually large temperature dependence of the splay elastic constant $K_1$ can be partly understood on the basis of an enhancement of the nematic order parameter $S$ by the smectic ordering.