Desorption spectra and surface structure. Carbon monoxide + tungsten system

Abstract

The influence of surface structure on the chemisorption of carbon monoxide on tungsten has been examined by comparing desorption spectra from polycrystalline and single crystal ribbons, exposing predominantly (100)+(111) and (113) planes respectively. Although a β₂ state is apparently absent on the (113) surface, in practice the desorption spectra are identical in the number of absorbed states, the activation energies of desorption, and the ratio of β₁ to β₂+β₃ molecules. The results indicate that the multiplicity of adsorbed states is not due to the natural heterogeneity of the surface in the CO + tungsten system. An alternative mechanism is discussed involving cluster formation in the β-layer.