An angle resolved photoemission study of the interaction between bromine and a copper (001) surface

The dissociative adsorption of bromine on a Cu(001) single crystal surface has been studied at room temperature by angle-resolved photoemission. There are two distinct stages in the bromine uptake before a c(2 × 2) chemisorbed layer is formed following a total exposure of ca. 2.5 L. Further exposure leads to the growth of a cuprous bromide layer at the surface. The c(2 × 2) bromine overlayer gives rise to adsorbate-adsorbate interactions which are strong enough to produce dispersion in adsorbate derived bands. An adsorbate-induced feature appearing at the Surface Brillouin Zone centre and 1.8 eV below the Fermi level is shown to have E( \ ̄ gG 5) symmetry. The main bonding contribution seems to result from the interaction between Cu 4s and 3d z 2 bands and the bromine 4p z orbital.