ADSORPTION OF H2O ON BI2SR2CACU2O8 AND GRAPHITE STUDIED WITH HREELS

We report vibrational spectra of H2O adsorbed on the (001) surface of Bi2Sr2CaCu2O8 (Bi 2:2:1:2) single crystals at 88 K. Spectra were measu red with high-resolution electron-energy-loss spectroscopy (HREELS) fo r exposures from 0.5 to 1.5 langmuir, and similar data were measured u sing a graphite substrate for comparison. On both substrates, the adso rbed H2O exhibited molecular adsorption and formed hydrogen-bonded clu sters over the range of exposures studied. These observations confirm that H2O binds weakly to the (001) surface of Bi 2:2:1:2, in agreement with photoemission results for the same system.