Contribution of Water Molecules to the Electronic Dipole Moment across the Gold-Water Interface

Understanding metal-water interfaces is instrumental in developing electrochemical cells for energy conversion. In this Letter, we quantify the relative contribution of the metal surface and the solvent molecules to the electronic component of the interfacial dipole moment enabled by an implementation of partially occupied Wannier functions that allows us to treat interfacial water in contact with metallic surfaces. Our calculations show that the contribution of the solvent is of overriding importance and that it mostly originates from specific deformation of the water lone pairs very close to the metal surface.