The Adsorption of CO and Oxygen on Cu Layers on a W(110) Surface,
Abstract
The adsorption of CO, and to a lesser extent that of oxygen on Cu layers deposited on a W(110) surface has been investigated by thermal desorption, Auger, and XPS measurements. For CO the amount adsorbed decreases monotonically with Cu thickness from 1-5 layers. For 0 there is a slight increase for 1 layer, followed by a steep decrease up to 4 Cu layers where the amount adsorbed levels off. CO adsorption shifts the core levels of Cu (observed for 1 layer of Cu) to higher binding energy by 0.4 eV; the 0 ls level of CO is also shifted to higher binding energy by 1.5 eV; relative to CO/W(110) suggesting that electron transfer from CO occurs but is passed on the underlying W. For 0 adsorption there is very little shift in the Cu core levels or in the 0 ls level, relative to 0/W(110). Thermal desorption of CO at saturation coverage Cu1/W(110) shows desorption peaks at 195, 227, and 266 K, as well as small peaks associated with C0 desorption from clean W, namely a peak at 363 K and beta-desorption peaks at 1080 and 1180 K. As C0 coverage is decreased the 195 and 227 K peaks disappear successively; the W-like peaks remain unchanged in intensity. It is argued that the latter may be due to adsorption on bare W at domain boundaries of the Cu overlayer, while the 190-266 K peaks are associated with adsorption on Cu, but probably involve reconstruction of the Cu layer. The effect of tungsten electronic structure on the behavior of adsorbates on the Cu overlayers, as well as similar effects in other sandwich systems are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 25, 1985
- Accession Number
- ADA147345
Entities
People
- I. M. Hamadeh
- R. Gomer
Organizations
- University of Chicago