An electron energy loss study of aluminum single crystals exposed to carbon monoxide

Aluminum single crystals of orientations {111}, {110}, and {100} were exposed at room temperature to carbon monoxide. The electron energy loss spectra of the exposed surfaces (> 20000 L) were essentially the same as those of clean surfaces. Since such spectra are very sensitive to small amounts of absorbate (e.g., 0.001 to 0.01 monolayer of oxygen), it is inferred that carbon monoxide does not adsorb on these clean low-order faces at room temperature. Similar results were obtained on polycrystalline and evaporated film samples. This finding contrasts with previous work on aluminum exposed to carbon monoxide.