Modeling Electrochemical Interfaces in Ultrahigh Vacuum: Molecular Roles of Solvation in Double-Layer Phenomena

Abstract

Some virtues of modeling electrochemical systems by dosing interfacial components onto clean metal surfaces in ultrahigh vacuum (UHV) are discussed, with an emphasis on elucidating the nature of double-layer solvation and how solvent molecules influence the intermolecular interactions. This “non situ” strategy (as distinct from ex situ approaches involving electrode transfer to/and from UHV) allows each interfacial component (solutes, ions, solvent) to be added sequentially and in controlled amounts, enabling the various molecular (and hence intermolecular) ingredients that constitute the double layer to be accessed in incremental fashion. The approach also provides an invaluable means of understanding the differences in structure and bonding between analogous electrochemical interfaces and the constituent metal−UHV systems. Such issues are particularly germane with the recent advent of microscopic-level structural information for in situ electrochemical systems. Described specifically here is the UHV-bas...