Structures of D₂ on MgO-Powder

Abstract

The structure of D 2 monolayers adsorbed on MgO-powder with a highly studied with elastic neutron scattering. A commensurability of the adsorbate along the [100]-direction of the substrate has been detected for all coverages. Thus the D 2 molecules are arranged in rows. At the highest measured monolayer coverage the spreading pressure accidentially adjusts the distance between the molecules along the rows so that a quasi hexagonal structure appears. This degeneracy is raised if the molecules relax along the rows with decreasing coverage and different types of ordering, i.e. commensurabilities along the rows, have been observed.