A quantum-mechanical approach is proposed for determining the activation energy of surface diffusion for adsorbed atoms of copper, nickel, zinc and iron on a copper substrate during electrocrystallization for various substrate overpotential. The calculation of the activation energy of surface diffusion is performed through the total energy of the crystal. An increase in the activation energy of surface diffusion with an increase in the surface potential is associated with an increase in the binding energy of the ad-atom with the substrate