Low temperature adsorption of CO on plycrystalline molybdenum, studied by X-ray and vacuum UV photoelectron spectroscopy

✍ Scribed by S.J. Atkinson; C.R. Brundle; M.W. Roberts

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 397 KB
• Volume: 24
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(74)85427-8

✦ Synopsis

The adsorption of CO on a polycrystaliine MO fdm at =80"K has been studied by X-ray and UV photoelectron spectroscopy (XPS and UPS). Two adsorption states were revealed by XPS. the ratio of the O(ls) intensities from these two states was about 4 : 1 at saturation coverage (PC0 = lad torr). Broad resonances corresponding to the MO's of CO(ads) are observed in the UPS spectrum. On warming to room temperature chemical shifts of about 1.2 ad 1.9 eV to lower biding energies were observed for the O(ls) and C(ls) signals of the major CO(ads) component. The minor state desorbed as anticipated from previous adsorption studies The XPS spectrum observed at room temperature was virtually identical to that previously reported for CO adsorbed at room temperature.

On warming the 'orbital structure' of adsorbed CO revealed by UPS is replaced by a structure apparently characteristic of carbon and oxygen atoms. These results suggest that low temperature adsorption takes place predomimnt-Iy into a molecular state which on warming to room temperature dissociates.