Alkali–metal adsorption on metal surfaces

✍ Scribed by J.M. Chen

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 983 KB
• Volume: 298
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(74)90046-5

✦ Synopsis

Results of low energy electron diffraction and work function studies of alkalimetal adsorption on metal surfaces are presented. The adsorption of Na on W( 112) surfaces resulted in the formation of one-dimensionally periodic arrays which underwent a continuous compression with increasing Na coverage. Coadsorption of Na with 0 resulted in a W-0-Na double layer, regardless of the sequence of deposition of th,e adsorbates. A similar behavior was found for (Cs+O)/W(lOO), (Cs+H)/W(lOO) and (Cs+O)/W(112) systems. It was also founo! that the underlying electronegative layer increased the interaction among alkali atoms and improved their tong-range order. Experimental worlc function data of alkali-covered surfaces have been compared with results of recent theoretical calculations. The data indicate that coadsorption of 0 or H on the surface has the effect of displacing the alkali atoms away from the substrate and reducing their energy level width. A strong interaction of adsorbates with substrate atoms was observed in the case of Cs and 0 coadsorption on Ni( 100) surfaces. The presence of a fractional monolayer of Cs increased the oxidation rate of a Ni(100) surface by about thirteenfold. The NiO formed in two crystallographic orientations depending on the initial Cs coverage.