Reflection anisotropy spectroscopy: A new probe for the solid-liquid interface

Introducing reflection anisotropy spectroscopy (RAS) as a new probe for sol id-liquid interfaces, we present results for the Au(110)/electrolyte interf ace which serves as a model system. We demonstrate that RAS is sensitive to surface phase transitions, step morphology, and electronic surface states. Using an empirical approach, the RA spectra are reproduced and features ar e identified which reflect the known character of the bias voltage driven ( 2 x 1) to (1 x 1) phase transition. RAS is established as an experimental t echnique to probe the electronic structure of solid-liquid interfaces in re al time to study a wide range of interface properties.