Adsorption on a Free-electron Metal

In this section we summarize the main results in simple and idealized schemes. We consider adsorption on a free electron metal, and on a transition metal. In particularly the adsorption of a molecule on a metal with d states is of great interest for catalysis. 

A free-electron metal only possesses a broad sp band. Upon approach, the electron levels of the adsorbate broaden and shift down in energy, implying that the adsorbate becomes more stable when adsorbed on the metal. The interaction results in a bonding energy of typically 5 eV for atomic adsorbates on metals. The situation is illustrated in Fig. 6.23. 

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