Item

Abstract

The formation of carbonate species (CO₃) on Ag(100) by exposure of the (4×1) oxygen-reconstructed surface to CO₂ has been studied with high-resolution electron energy loss spectroscopy (HREELS). The position and shape of the CO₃-related loss peaks were found to depend on the long-range order in the carbonate layer, as observed with LEED. In addition to the γ, ν_s and ν_as modes of CO₃ at 833, 1050 and 1343 cm⁻¹, two separate peaks in the Ag–CO₃ frequency region occur at 277 and 239 cm⁻¹. The latter is particularly sensitive to disorder. Coadsorbed CO₂, which is stabilized by the CO₃, exhibits vibrations that are almost unchanged compared to the gas phase values, although the Fermi resonance appears to be largely suppressed.