International Research Fellowship Program: Fifth Order Infrared Spectroscopy 3-D-IR of Hydrogen-bonded Systems

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Garrett-Roe0601907The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Sean A. Garrett-Roe to work with Dr. Peter Hamm at the University of Zurich in Switzerland.A typical liquid has a density of about 50 atoms/nm3. Because the atoms and molecules are so tightly packed, they interact -- molecules collide, bonds break, and new bonds form. These interactions are the subject of solvation experiments, which measure the coupling of a solute to the low frequency modes of a solvent. The PI proposes to develop a new spectroscopic technique (3D-IR), in collaboration with Prof. Peter Hamm, to see how the solvation modes are coupled to each other. Molecular dynamics (MD) simulations can access this kind of information, but no current experiment can measure it accurately. This new technique will be used to probe the dynamics of hydrogen-bonded systems (liquid water and peptides in protic solvents). This work will involve both developing the theory of non-linear optical spectroscopy as well as the experimental instrumentation. They will see, for the first time, how the fast motions of water are coupled to the slower reorganization of the hydrogen-bonding network. In other words, 3D-IR will show how the dynamics of a water molecule depend on the local structure of the neighboring water molecules. This may clarify the physical mechanisms of hydrogen-bond making and breaking. This fundamental research will have important consequences for many applications in chemistry and biology; most noteworthy are molecular dynamics simulations of biological systems.