Atomic Relaxation at Ordered Electrochemical Surfaces Probed by Scanning Tunneling Microscopy: Au(111) in Aqueous Solution Compared with Ultrahigh-Vacuum Environments.

摘要

Detailed surface atomic rearrangements at the ordered Au(111)-aqueous interface triggered by negative electrode charges are examined by in-situ scanning tunneling microscopy (STM). Not only the atomic reconstruction, but also the longer range superstructures, formed at this electrochemical interface are seen to be remarkably similar to those observed previously by STM on clean Au(111) in ultrahigh vacuum. Understanding the atomic structures formed at ordered monocrystalline metal surfaces by reconstruction, both in the absence and presence of adsorbates or other means of modifying the surface environment, constitutes a centrally important topic in surface science. Almost all the experimental information on surface reconstruction gathered so far refers to metal-ultrahigh vacuum (uhv) interfaces, where electron diffraction and related techniques can be employed. Similar phenomena are anticipated at metal-solution (i.e., electrochemical) interfaces, where the electrode potential offers a powerful additional means of altering the chemical and electrostatic surface state.