The formation of carbonate on Ag(110) studied by high-resolution EELS

The formation of carbonate species (CO3) on Ag(110) by exposure of the (4 x 1) oxygen-reconstructed surface to CO, has been studied with high-resoluti on electron energy loss spectroscopy (HREELS). The position and shape of th e CO3-related loss peaks were found to depend on the long-range order in th e carbonate layer, as observed with LEED. In addition to the gamma, v(s) an d v(as) modes of CO3 at 833, 1050 and 1343 cm(-1), two separate peaks in th e Ag-CO3 frequency region occur at 277 and 239 cm(-1). The latter is partic ularly sensitive to disorder. Coadsorbed CO2, which is stabilized by the CO 3, exhibits vibrations that are almost unchanged compared to the gas phase values. although the Fermi resonance appears to be largely suppressed. (C) 1999 Elsevier Science B.V. All rights reserved.