The properties of CO and K co-adsorbed on Ni(111), studied by thermal desorption and metastable quenching spectroscopy
We use thermal desorption and metastable quenching spectroscopy to study the (CO+K)/Ni(111) system. We find that CO and K co-adsorption increases the binding energy (to the surface) of both molecules; that at coverages of more than one potassium atom per, roughly, eight nickel atoms the adsorbed CO...
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Veröffentlicht in: | The Journal of chemical physics 1985, Vol.82 (1), p.485-495 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We use thermal desorption and metastable quenching spectroscopy to study the (CO+K)/Ni(111) system. We find that CO and K co-adsorption increases the binding energy (to the surface) of both molecules; that at coverages of more than one potassium atom per, roughly, eight nickel atoms the adsorbed CO molecules exchange atoms; that this exchange takes place without formation of a detectable (by MQS) number of adsorbed carbon and oxygen atoms; that the 2π* peak in the Penning spectrum is enhanced by the presence of the potassium; that at high potassium coverages CO and K desorb at practically the same temperature giving rise to a very narrow thermal desorption peak. We discuss the spectroscopic evidence concerning the detection of the 2π* orbital. We suggest that our experiments indicate that at low potassium coverage the surface has two local work functions: one corresponds to Ni atoms unmodified by the presence of potassium, and the other to strongly modified, low work function sites. |
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ISSN: | 0021-9606 1089-7690 |
DOI: | 10.1063/1.448771 |