THE ADSORPTION OF METHANOL ON AG(111) STUDIED WITH TDS AND XPS

The adsorption of methanol on Ag(111) is studied using thermal desorpt ion spectroscopy (TDS) and X-ray photoelectron spectroscopy (XPS). It is found that methanol adsorbs reversibly. The TDS spectra reveal thre e different states. These states can be assigned to molecules desorbin g from the monolayer, the crystallised multilayers and the two amorpho us multilayers which are located between the two other phases. This is the first time that these three states are seen by means of TDS. This multilayer behaviour of methanol most likely also applies to other me tals. The sticking coefficient is found to be coverage independent fro m the submonolayer into the multilayer regime. The desorption energy i s found to be 0.41 eV. XPS shows or both the oxygen and carbon a small shift to higher binding energies with increasing exposure.