DFT calculations of the interaction of alkali ions with copper and silver

The interaction of alkali ions with the Cu(100) and Ag(100) surfaces is studied using the DFT method. The results of the B3LYP calculations performed for five cations, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺, adsorbed on the surface of the M₁₂(6,6) cluster (M=Cu, Ag) are presented. On both metals the interaction is found to be strongest for the Li⁺ ion and weakest for the Cs⁺ ion. Three sites were tested for the adsorption of ions on the (100) surface: top, bridge and hollow. For the two smaller ions, Li⁺ and Na⁺, the hollow site is found to be the most stable. For the three larger ions the top position is more attractive. Nevertheless, the energy value at the different sites for a given ion in most cases, differs by less than 5 kJ mol^?1. For all ions the interaction with silver is stronger than the interaction with copper.