Liquid interfaces: A study by sum-frequency vibrational spectroscopy

Liquid interfaces play a fundamental role in science and technology. The development of surface-sensitive probes capable of yielding molecular information about these interfaces is of great importance. This paper gives an overview of our and some others' recent work on vibrational spectroscopy of liquid interfaces by the sum-frequency generation (SFG) technique. This technique, being highly surface specific and applicable to all interfaces accessible by light, has been proven to be a most powerful analytical tool for liquid interfaces. A wide range of systems have been studied including neat liquid surfaces, solid/liquid and liquid/liquid interfaces, surfactants at liquid interfaces, and electrochemical interfaces. In many cases, SFG is shown to be the only technique available that can provide detailed information about a liquid interface at the molecular level.