Theory of chemisorption based on a surface molecule plus indented solid model

Paulson and Schrieffer's theory (1975) of hydrogen chemisorption on a metal surface based on a surface molecule plus indented solid model is extended to include mixing of the neutral and ionic states of the adatom. The chemisorption energy and the wavefunctions are calculated in a strong-coupling approximation by using a surface Green function. It is shown, firstly, that the contribution of the ionic states is of great significance, and secondly, that neglect of substrate band effects introduces a serious error. The role of substrate electron interactions is also investigated.