DIRECT DETERMINATION OF THE LATTICE SITE OF H-ATOMS ON THE (1 X-2) RECONSTRUCTED CU (110) SURFACE

In this work we present preliminary results of a low-energy ion scatte ring (LEIS) study of a H-induced (1 x 2) reconstruction of the Cu (1 1 0) surface. The surface was bombarded with 6 keV Ar+ ions. Time-of-fl ight (TOF) azimuthal and polar scans of scattered Ar and recoiled Cu a nd H were measured at a scattering angle of 45 degrees. To interpret t he results obtained, the azimuthal scans were simulated using a new co mputer program ''MATCH'' and fitted to the experimental data. The surf ace was found to be of the (1 x 2) ''missing row'' reconstruction type . A number of positions for H atoms at the reconstructed surface menti oned were analyzed. The H atoms were observed to be situated in one of two possible trigonal hollow sites as was found before. The desorptio n and adsorption of H were studied. Desorption from the Cu (1 1 0)-(1 x 2) surface was observed in the temperature range 250-300 K. Above 30 0 K complete desorption results in de-reconstruction. In the adsorptio n measurements, the H-saturation took place after an exposure equivale nt to 1.4 L at a sample temperature 230 K. (C) 1998 Elsevier Science B .V.