General Considerations of Adsorption on Surfaces

In both cases, the adsorbate occupies the T positions with half coverage and the unit cell is then doubled in the h and k directions so the Wood s notation for this 

Four common examples of substrate coverage on an fee strueture. The surfaee metal atoms are represented by shaded circles and the absorbate by white circles. The heavy line outlines the new unit cell for each example. 

Schematic energy versus density of states plots for the d states of (a) the metal bulk and (b) the metal surface. The Fermi level and mean d orbital energy are given by ep and e, respectively, (c) A plot of the computed CO binding energy to a Pt surface versus the calculated e. (Adapted from Reference [11].) 

Alkali metals and sulfur are common co-adsobates. They act as chemical modifiers, speeding up or slowing down reactions. For example, there is no isotopic mixing using a mixture of C 0 and C 0 on Rh(l I I) [13]. However, the addition of 20% of a monolayer coverage of potassium causes roughly three CO molecules to dissociate per potassium atom. It creates a 17 kcal/mol increase in the 

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