Smectic-APhase with Two Collinear Incommensurate Density Modulations

Abstract
The first observation of a smectic-A phase with two collinear incommensurate density modulations is reported. X-ray diffraction studies of this incommensurate phase reveal reflections corresponding to both partially bilayer (Ad) and bilayer (A2) periodicities, the relative intensities of the two reflections being strongly temperature dependent.