THE INTERACTION OF ATOMIC-HYDROGEN WITH CU(110)

The interaction of atomic hydrogen with Cu(110) has been investigated by thermal desorption spectroscopy and by surface state spectroscopy using ultraviolet photoemission and inverse photoemission. Atomic H first forms a chemisorption layer, which saturates at a coverage of approximately 0.5 monolayers. At low temperature further exposure leads to a thermal desorption peak which was not observed hitherto. We attribute it to H absorption into subsurface sites. The surface state shifts caused by the adsorption of hydrogen on Cu(110) show striking parallels to those observed upon hydrogen adsorption on Ni(110). The (1 x 2) reconstruction of the H/Cu(110) surface gives rise to a surface state shift which is characteristic for a missing or added row phase. The intensity variation of the surface states during the formation of the (1 x 2) phase indicates the formation of large islands. An occupied surface state on H/Cu(110) contributes to the stabilization of these islands.