This grant is in the general area of analytical and surface chemistry and in the subfield of laser spectroscopy of liquid solid interfaces. Professor Robert Corn will develop the theoretical and experimental description of monolayers of mixed molecular species at metal electrode interfaces. The second harmonic generation and sum frequency generation methods developed by Professor Corn will be combined with infrared spectroscopic measurements of mixed monolayers of molecular species controlled by electrochemical potential on a metal electrode. These studies will allow fuller understanding of the role of interfacial molecular structure on electron transfer processes which occur at these interfaces. In addition, the methodology will allow more complete description of other liquid solid interfaces of import in a variety of chemical and technological processes. By combining second harmonic generation (SHG) on and off resonance analysis and theoretical description of the response using Pople-Pariser-Parr formalism to describe the molecular polarizability tensors, the first measurements of molecular orientation response in SHG have been made. Professor Corn will extend these measurements in combination with infrared reflection absorption and sum frequency generation to fully characterize mixed monolayers of molecular species at single crystal electrode liquid interfaces.
