The electronic structure of Cu(110) and Ag(110) surfaces studied by reflection anisotropy spectroscopy

Experimental curves for the normalised azimuthal reflection difference Delt a r/r for clean and oxygen-reconstructed Cu(110) and Ag(119) between 1.5 an d 5.5 eV are presented. The copper spectra contain resonances at 2.1 eV and around 4 eV. Using expressions for the screened dipole-dipole interaction we have found that both the surface local-held effect and polarisation-depe ndent transitions between surface states at the (Y) over bar point of the s urface Brillouin zone are responsible for the main features in the spectra. In the silver spectra thee is a resonance at 1.7 eV originating from polar isation-dependent transitions between surface states. The changes in the si gnals upon formation of ordered oxygen overlayers Cu(110)(2 x 1)-O and Ag(1 10)(2 x 1)-O are discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved.