Vibrational spectra of CO adsorbed on iridium alloys

The vibrational spectra of carbon monoxide chemisorbed on alloys of Ir-Rh, Ir-Pd, Ir-Pt and Ir-Cu of different composition have been investigated at temperatures from 30 to 400°C. It has been shown that the surface of an alloy does not correspond in its properties to a simple mixture of the two components concerned. In the case of CO chemisorbed on Ir-Rh, Ir-Pd and Ir-Cu, a lowering of the frequency of CO has been observed. This effect is probably due to electron transitions between the alloy components.