Molecular dynamics, density functional theory of the metal-electrolyte interface

Quantitative, predictive theories for metal-electrolyte interfaces require an atomic-scale representation of the interface, which must include an accurate statistical description of a polar fluid in contact with a solid surface; and also a description of the electronic density and structure of a metal surface in contact with a fluid. Such a complex system presents a difficult computational problem, and has been dealt with in the past essentially by parts; either by molecular dynamics calculations of the fluid structure, or density functional calculations of the metal-surface electronic structure. A complete and self-consistent determination of the surface structure would, however, involve a simultaneous calculation of both the atomic and electronic structure of the interface. This suggests a combination of these two calculational techniques, and it is just this sort of molecular dynamics and density functional combination which comprises the Car-Parrinello, and related, methods. We have developed a Car-Parrinello type combination of molecular dynamics and density functional methods, suitable for application to the metal-electrolyte interface. We briefly describe this calculation and discuss our initial results for a fairly simple metal-water interface.