Structure of the metal-electrolyte solution interface: Theoretical results for simple models

Theoretical results are given for electrolyte solutions in contact with uncharged metallic surfaces. The metal is represented by a jellium slab and the electron density distribution across the interface is obtained using density functional theory. The solution ‘‘structure’’ is found by solving the reference hypernetted-chain approximation. The two interfacial phases interact electrostatically and fully self-consistent electron density distributions and wall-particle molecular correlation functions are calculated. The electron densities, wall-induced solution structure and the electrostatic potential drop across the interface are discussed in detail and compared with the inert wall case. It is found that a highly ordered region exists near the metal surface. The dipoles are strongly ordered by the metal field and this solvent structure effectively dictates the ion distributions. The direct ion-metal interactions are found to be less important.