Nancy E. Levinger is supported by an NSF Young Investigator Grant from the Theoretical and Computational Chemistry Program to perform experimental studies of polar solvation and chemical reactions at the interface between immiscible liquids. She will use surface second harmonic generation (SSHG) to perform initial studies on coumarin 153, a classic probe of solvation dynamics, at the liquid/liquid interface. SSHG is an ideal technique for studying interfacial chemistry because the signals arise solely from the interface without interference from the bulk medium. Information regarding molecular rotational reorientation and electron transfer reactions at interfaces can be examined by this method. A variety of liquid/liquid interfaces will be probed including the octanol/water interface which is an important model system for drug modeling of membrane solubility. Electron transfer and isomerization reactions will be studied at the liquid/liquid interface in a variety of immiscible liquid solvent systems including real membrane bound biologically important proteins. A wide range of chemistry occurs at interfacial boundaries. Examples range from biological and medicinal interfacial problems, such as chemistry of anesthesia, to industrial scale separations of metal ores across interfaces, to the relatively new investigations into self assembled monolayers and Langmuir-Blodgett films for nanoelectronics and nonlinear optical materials. These problems are based not only on structure and composition of the interface but also on kinetic processes that occur at interfaces. As such, there is considerable interest in chemical dynamics at interfaces. Levinger has developed a tool to directly probe the chemical dynamics occurring at such interfaces, and will apply this technique to a variety of important and technologically relevant problems.
