Total internal reflection vibrational sum frequency spectroscopy is used to probe the liquid/liquid interface in these studies supported by the Analytical and Surface Chemistry Program. Professor Richmond and her colleagues at the University of Oregon are probing the hydrogen bonding of water at the water/hydrocarbon interface. They are also investigating the structure and dynamics of alkyl surfactant molecules at the oil/water interface, providing important information about the changing conformation of these molecules adsorbed at the interface. This provides the basic groundwork for understanding ion and molecular transport across membranes and other biologically important structures. Using methods of non-linear spectroscopy developed in Professor Richmond s laboratories, the structure and dynamics of molecules at the oil/water interface form the focus of this research project. Understanding the arrangement and motion of molecules at this interface is important to the operation of many vital biological processes, including respiration and transport of nutrients in the body. This research provides both the conceptual understanding of these important processes, as well as the tools needed to study them.