Statistical-thermodynamic analysis of changes in the electron density at the surface of a metal caused by adsorption
It was demonstrated that the adsorption of small amounts of neutral or charged species is accompanied by an increase or a decrease in the surface electron density ne in the metal-adsorbent. The dissolution of the adsorbate in the subsurface layer of the metal was found to influence the value of ne. A consequence of ne being dependent on the amount of the adsorbate is the modification of the free surface of the metal and a change in the adsorbate-adsorbent bond strength for both chemisorption and physical adsorption. A theoretical analysis of the effect of surface additives (modifiers) is in agreement with the available experimental results.