Orientation of Methylene Blue Molecules Adsorbed on Solids

The author has investigated the state of orientation of methylene blue molecules absorbed on rubbed glasses. Reflection spectra made with polarized visible radiation demonstrate conclusively that the long axis of the molecules is perpendicular to the direction in which the glass was originally rubbed. Absorption spectra with polarized infra-red radiation show, in addition, that the molecules are adsorbed on the glass with the plane of their benzene ring parallel to the glass.