Ultrafast dynamics of supercritical fluid solutions

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In this project, funded by the Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division, Professor Lawrence D. Ziegler of Boston University will conduct a series of experiments that use ultrafast laser spectroscopic methods to learn about the special properties that allow supercritical fluids (SCFs) to be such effective solvents, as compared to normal liquids. These studies are designed to reveal how motions on the time scale of hundreds of femtoseconds to hundreds of picoseconds account for this extraordinary solvation ability. A combined experimental and computational approach will be carried out to accomplish these goals in collaboration with several theorists at Boston University. Graduate and undergraduate students will participate in this research, and will be trained in state-of the-art methods. In addition, participants in PROSTARS, an NSF sponsored program to enhance research opportunities for local community college students, and in the NSF RET (Research Experience for Teachers) program, as well as students in the women's college of Wellesley, will be encouraged to participate in these studies during the summer months of this award. A supercritical fluid is so highly compressed that it is neither a gas nor a liquid. SCFs have unique and useful combinations of gas and liquid properties. Many investigators are exploring ways to use SCFs to replace traditional solvents, which can be toxic, flammable or difficult to remove, because they because they dissolve mixtures well as if they are liquids, but have easily changed densities and thus can be more easily removed or processed. Prof. Ziegler's research will help scientists understand what gives SCFs these unusual properties so that they can be used more effectively and in a wider range of applications.