Molecular and Ionic Interactions at the Oil/Water Interface as Measured bySurface Second Harmonic Generation and Sum-Frequency Generation

摘要

Direct measurement of molecular properties of these fluid interfacial regionsremains a challenging task. In recent years we have been applying two techniques to such problems, surface second harmonic generation (SHG) and sum-frequency generation (SFG). The success that we have had in making measurements of the structural and molecular properties of a variety of neat hydrocarbon/water interfaces and dichloroethane/water interfaces has come from employing a total internal reflection geometry (TIR). We have examined interfacial order, molecular orientation and ionic adsorption at various of water interfaces with TIR SHG and TIR SFG. The results provide a valuable insight into how molecules and ions interact at these fluid interfaces.