Infrared spectra of CO chemisorbed on a surface vicinal to Cu(110): The influence of defect sites

It has previously been reported that the infrared spectrum of CO chemisorbed on Cu(110) consists of a doublet band in the C-O stretching region. Experiments performed on a surface vicinal to Cu(110) indicate that the high frequency component of this doublet arises from CO molecules adsorbed at step or defect sites. Coupling with the low frequency component leads to these molecules exhibiting a much greater absorption intensity than would be expected from the small number of sites involved. This phenomenon is likely to occur in systems other than CO/Cu, and may be of major significance in the interpretation of spectra from supported metals.