Chiral and herringbone symmetry breaking in water-surface monolayers

Abstract

We report the observation from monolayers of eicosanoic acid in the ${\mathit{L}}_{2}^{\ensuremath{'}}$ phase of three distinct out-of-plane first-order diffraction peaks, indicating molecular tilt in a nonsymmetry direction and hence the absence of mirror symmetry. At lower pressures the molecules tilt in the direction of their nearest neighbors. In this region we find a structural transition, which we tentatively identify as the rotator-herringbone transition ${\mathit{L}}_{2\mathit{d}\mathrm{\ensuremath{-}}}$${\mathit{L}}_{2\mathit{h}}$. \textcopyright{} 1996 The American Physical Society.