Adsorption of Additives: Hardness and Softness at Electrified Interfaces

The search for effective additives is important for the development of new metal deposition processes. The hard/soft concept is a possible way for the selection of suitable substances. Hardness or softness are connected with molecular properties like electronegativity or the chemical potential of electrons. The density functional theory (DFT) provides methods for calculating the respective values. Corresponding function of the side of the electrode is the Fermi energy, the upper level of occupied electron energy levels. Hardness and softness of the electrode depend on the electrode potential. This dependence will be discussed.