Ultrafast Mechanics of Molecular Liquids and Solids: Vibrational and Structural Relaxation

本项目旨在从基础层面理解分子液体和固体的力学动力学。在两个截然不同但又相关的重大进展中，最大的进展涉及一种被称为三维（3D）红外-拉曼光谱的新技术的开发和使用。利用三维红外-拉曼光谱，可以研究振动能量如何在分子中流动，以及液态结构如何随时间演变。将研究室温下的重要液体，如水和甲醇，以改进激光装置并推进对3D光谱的理论理解。目前正在研制一种低温装置来研究这些液体和低温固体的温度依赖性。小推力涉及到冲击波光谱学技术的发展和使用，以研究具有缓慢结构弛豫动力学的过冷液体，如玻璃和聚合物。这项技术也被称为纳米冲击技术。它在材料中产生大幅度的结构扭曲，然后使用振动光谱来监测结构向原始结构的演变。该项目涉及开发新的仪器来研究能量流等现象，以及蛋白质和聚合物等复杂系统中的结构如何演变。该项目与结构和生物材料加速老化等主题的相关性很高，在这些领域接受培训的学生应该在材料和生物科学领域的就业市场上具有很强的竞争力。

This project aims to understand the mechanical dynamics of molecular liquids and solids at a fundamental level. The largest of two distinct but related thrusts involves the development and use of a new technique termed three dimensional (3D) Infrared-Raman spectroscopy. With three dimensional Infrared-Raman spectroscopy it is possible to study how vibrational energy flows through molecules, and how liquid state structures evolve in time. Important liquids such as water and methanol at room temperature will be studied to improve the laser apparatus and advance a theoretical understanding of 3D spectroscopy. A low temperature apparatus is being developed to study temperature dependence of these liquids and cryogenic solids. The smaller thrust involves the development and use of a shock wave spectroscopy technique to study supercooled liquids such as glasses and polymers which have slow structural relaxation dynamics. This technique is also referred to as the nanoshock technique. It produces large amplitude structural distortions in materials and then uses vibrational spectroscopy to monitor structural evolution back toward the original structure.This project involves the development of new instrumentation to study phenomena such as energy flow and how structures evolve in complex systems such as proteins and polymers. The relevance of this project to topics such as the accelerated aging of structural and biological materials is high, and students trained in these areas should be very competitive in the job market in areas of materials and biosciences of high interest to industry.