Different adsorption states on single substrate

Abstract

The adsorption of potassium and of CO on tungsten is examined with a view to defining the similarities and differences between metallic and covalent adsorption on the same substrate. It is concluded that metallic adsorption shows no distinctly different adsorption states, variations resulting from differences in substrate geometry and work function being quantitative rather than qualitative, while covalent adsorption shows definite, discontinuous changes in adsorption type, which can be correlated with differences in geometry and binding mode. In both cases, however, substrate-adsorbate geometry appears to be important even though the effect in metallic adsorption becomes obvious only after some dissection of the factors entering the heat of adsorption.