Theoretical discussion of the electrosorption valency

Consider the case where only one valence orbital is involved in the adsorption bond. We are interested in the energy of this level relative to the Fermi level of the metal, which will determine to which extent the energy levels are occupied. 

Since we are interested in equilibrium phenomena, fluctuations, and in particular, those of the solvation layer can be neglected. 

To determine the change in the free energy,, required to transfer an electron from of the metal to the ion in the bulk of the solution. We decompose the electron transfer process from the metal into separate steps  

As an ilustration, we consider Cs+ and Cl in aqueous solution near a polycrystalline gold electrode. We assume that both the metal and the solution are at the same outer potential. Then we get for Cs 161] 

These values merely confirm the well known fact that both ions are stable in the neighborhood of gold at the point of zero charge. 

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