Strong incommensurate fluctuations in a smectic-Aphase

Abstract
High-resolution x-ray scattering measurements on a liquid-crystalline smectic-A1 phase show two collinear diffuse maxima at incommensurate wave vectors in addition to a fundamental quasi-Bragg peak. These diffuse peaks are shown to agree qualitatively with calculated profiles; they indicate the close proximity of an incommensurate phase with two strongly coupled order parameters.