Water and methanol adsorption on MgO(100)/Mo(100) studied by electron spectroscopies and thermal programmed desorption

The adsorption of methanol (CH3OH) and water (D2O) on the MgO(100)/Mo(100) surface at 100 K has been studied by metastable impact electron spectroscop y (MIES), ultraviolet photoelectron spectroscopy (UPS (HeI)), and temperatu re programmed desorption (TPD). To acquire detailed information regarding t he initial stages of adsorption, TPD data, providing information about the relative surface coverage and the molecule-surface interaction, are compare d directly with MIES data, which provide information about the electronic s tructure of the adsorbed molecules. For water adsorption, a prominent multi layer desorption feature develops in the TPD before the entire surface is c overed, indicating 3D growth on the partially covered MgO(100)/Mo(100) surf ace. On the other hand, the formation of a methanol multilayer desorption f eature coincides with complete coverage of the surface.