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

Garrett-Roe 0601907国际研究奖学金计划使美国科学家和工程师能够在国外进行9到24个月的研究。该计划的奖项提供了联合研究的机会，以及使用独特或互补的设施，专业知识和国外的实验条件。Garrett-Roe博士与瑞士苏黎世大学的Peter哈姆博士合作。一种典型的液体的密度约为50个原子/纳米3。因为原子和分子是如此紧密地堆积在一起，它们相互作用--分子碰撞，键断裂，新的键形成。这些相互作用是溶剂化实验的主题，该实验测量溶质与溶剂的低频模式的耦合。PI建议与Peter哈姆教授合作开发一种新的光谱技术（3D-IR），以了解溶剂化模式如何相互耦合。分子动力学（MD）模拟可以访问这类信息，但目前没有实验可以准确测量。这项新技术将用于探测氢键系统（液态水和质子溶剂中的肽）的动力学。这项工作将涉及发展非线性光学光谱学的理论以及实验仪器。他们将第一次看到水的快速运动是如何与氢键网络的缓慢重组相结合的。换句话说，3D-IR将显示水分子的动力学如何取决于相邻水分子的局部结构。这可能阐明氢键形成和断裂的物理机制。这一基础研究将对化学和生物学的许多应用产生重要影响;最值得注意的是生物系统的分子动力学模拟。

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.