Adsorption on Bulk Metals

As discussed in Section 2.2, the maximum sensitivity in IRRAS is achieved with p-polarized radiation at grazing angles of incidence. With a single reflection, the method can detect CO adsorbed on Ir at 0.002-monolayer (ML) coverage [90]. A SNR on the order of 1000 can be reached, even with a conventional doublebeam dispersive spectrophotometer [91]. This is crucial for studies of catalysis 

ULTRATHIN FILMS AT GAS-SOLID, GAS-LIQUID, AND SOLID-LIQUID INTERFACES 

IRRAS studies of adsorption on metal surfaces began by Greenler [94, 95] and Low and McManus [96] in the 1960s. Since that time, IRRAS has become a relatively routine method that is used in numerous laboratories for investigating such phenomena as catalysis, corrosion inhibitors, self-assembly, and lubrication. Application of IRRAS to the study of adsorbed gases has been discussed in Refs. [25, 26, 97-121]. A summary can be found in Refs. [122-126]. 

One of the most thoroughly studied molecules in the history of IRRAS is CO, because it possesses only one internal vibrational mode, which is a strong oscillator, and can be isotopically labeled at either end. Thus far, adsorption of CO on Cu(lOO) [127-136], Cu (111) [137, 138], Cu (110) [139], and polycrystalline Cu [140] has been studied. Due to a strong interaction between adsorbed CO and Pt, Ni, Rh, Ir, and Pd, fine details of this phenomenon have been extensively investigated. In particular, adsorption of CO on Pt (111) [141-155], Pt 

The position of the vCO band depends on the Cu crystallographic plane [108]. The low-index Cu(lOO) and Cu(l 11) surfaces give bands at 2080 and 2076 cm , respectively, while the Cu(llO), Cu(311), Cu(211), and Cu(755) surfaces give bands between 2096 and 2110 cm , close to the band positions for evaporated polycrystalUne Cu and supported Cu (2100-2103 cm ). This effect has been attributed [108] to a predominance of stepped or higher index planes at the surface of the evaporated films and snpported Cu. 

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