X-ray diffraction study of the structure of a monolayer methanol film adsorbed on graphite

Abstract

The x-ray diffraction measurements of methanol adsorbed on graphite have been taken over the temperature range 32–150 K and the coverage range 0.02–0.17 molecule Å−2. The diffraction data are analyzed to yield the configuration of the molecule on the surface by means of the least-squares fitting of the whole pattern. The data show clearly that zigzag chains of alternating weak and strong hydrogen bonds, as evidenced by the long and short 0⋅⋅⋅0 separations, are formed in the crystalline monolayer of methanol on graphite. The crystalline solid film near the complete monolayer melts around 142 K in comparison to bulk methanol which melts at 175.4 K.