The adsorption and decomposition of Fe(CO) 5 on fcc and bcc iron films at 90 K were investigated using infrared reflection absorption spectroscopy (IRRAS). The fcc film was epitaxially grown on a Cu(1 0 0) crystal at room temperature, whereas the bcc film was deposited as polycrystalline by electron-beam evaporation onto a Si(111) wafer. The saturated adsorption of Fe(CO) 5 on the fcc Fe(1 0 0) surface yielded a dominant IRRAS band at 2060 cm -1 due to the axial C-O stretch mode of Fe(CO) 5 . Upon UV (254 nm) irradiation to the adsorbed layer, the 2060 cm -1 band decreased in intensity and a new band appeared at 2072 cm -1 , indicating the photolytic decomposition of the adsorbed Fe(CO) 5 . Fe(CO) 5 adsorption on the polycrystalline bcc surface gave rise to a single intense band at 2072 cm -1 which was not changed in position by UV irradiation. We conclude from these results that the fcc(1 0 0) surface is inactive for the decomposition of Fe(CO) 5 in comparison to the polycrystalline bcc surface.
- Infrared absorption spectroscopy
- Iron films
- Molecular beam epitaxy