Electron spectroscopy and adsorption studies: Chemical shifts in X-ray photoelectron and auger spectra for monolayer adsorption

✍ Scribed by C.R. Brundle; A.F. Carley

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 496 KB
• Volume: 33
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(75)85449-2

✦ Synopsis

A range of transition metal film substrates (MO, W, Pt, Ni, Fe, Cu. V, Zn) exhibit no clear chemical shifts in their ESCA or Auger peaks on adsorption of a monolayer equivaent of oxygen or carbon monoxide, though in some cases agmmetribroadening of the peaks may be ascribab!e to a small chemical shift of a component of the peak. This compares to the large shifts that WI occur in these peaks on bulk oxidation to many atomic 1ayr;rs depth. In addition the spectra of the clan substrates sholv no indication of a difference in the surface layer of atoms. These results are not unexpected, but are in contradiction to some previously reported data. They suggest that attempts to follow chemisorption processes by monitoring chemical shifts of sabstrare peaks are likely to prove unsuccessful in many ceses involving trarktion metals, putictirly for common spectrometer geometries (30" to 60" ejection angle). Changing to grazing exit angle wil! increase the probability of observing small shifts for the outer substrate atoms by reducing the effective escape depth.