Dynamics in Complex Molecular Condensed Matter Systems

该项目旨在利用各种超快非线性光学和红外实验和理论来增加对玻璃和复杂液体的理解，如过冷液体、液晶和氢键液体（水和醇）。超快红外振动回波、光谱分辨振动回波和振动回波相关光谱将用于研究氢键体系，如甘油、正常液体、过冷液体和玻璃的动力学。振动回波实验为氢键网络动力学提供了直接的探测。超快（100fs）到慢速（ms）光外差检测光学克尔效应实验将用于研究过冷液体、玻璃化转变、液晶和离子有机液体的方法。液体和模式耦合理论之间的比较将提供对动力学，分子间相互作用和结构之间联系的见解。使用可见光和红外光的超快脉冲序列的新工具和实验方法正在开发和应用，以获得对此类系统的理解。这些方法允许在重要事件发生的时间尺度上检查变化的分子结构。参与各方面研究的研究生和博士后将培养下一代一流的科学家。无序分子材料，如液体和玻璃，在天文学、动物学以及化学、材料科学和生物学等广泛的科学领域中发挥着重要作用。晶体是有序的固体。它们的结构是固定的。利用x射线晶体学，分子和原子的排列是众所周知的。液体，特别是复杂的液体，如液晶、醇、水和玻璃（无定形固体），与晶体有很大的不同。它们没有固定的结构，而且结构是不断变化的。即使是固体的玻璃也没有固定的结构。这些结构随着时间的推移而演变。复杂液体和玻璃的宏观性质取决于其微观结构和动力学之间关系的细节。对复杂分子系统的解释可以引导它们的控制和利用。研究生和博士后参与研究的各个方面，培养下一代一流的科学家。液体和玻璃对工业来说是非常重要的材料，在这些领域受过训练的学生将在高科技就业市场上极具竞争力

This project aims to use a variety of ultrafast nonlinear optical and infrared experiments and theory to increase understanding of glasses and complex liquids, such as supercooled liquids, liquid crystals, and hydrogen bonding liquids (water and alcohols). Ultrafast infrared vibrational echoes, spectrally resolved vibrational echoes, and vibrational echo correlation spectroscopy will be used to study the dynamics of hydrogen bonded systems, such as glycerol, as normal liquids, supercooled liquids and glasses. The vibrational echo experiments provide a direct probe of hydrogen bond network dynamics. Ultrafast ( 100 fs) to slow (ms) optical heterodyne detected optical Kerr effect experiments will be used to study supercooled liquids, the approach to the glass transition, liquid crystals, and ionic organic liquids. Comparisons among the liquids and to Mode Coupling Theory will provide insights into the connection between dynamics, intermolecular interactions, and structure. New tools and experimental methods using ultrafast pulse sequences of visible and infrared light, are being developed and applied to gain understanding of such systems. The methods permit examination of changing molecular structures on the time scales on which the important events occur. Graduate students and postdoctoral students participating in all aspects of the research will train the next generation of first-rate scientists. %%%Disordered molecular materials, such as liquids and glasses, play important roles in a wide range of scientific fields from astronomy to zoology, as well as in chemistry, materials science and biology. Crystals are ordered solids. Their structures are fixed. Using x-ray crystallography, the arrangement of the molecules and atoms is well known. Liquids, particularly complex liquids, for example, liquid crystals, alcohols, and water, and glasses (amorphous solids), are very different from crystals. They do not have a regular structure and the structure is constantly changing. Even glasses, which are solids, do not have fixed structures. The structures evolve with time. The macroscopic properties of complex liquids and glasses are determined by details of the relationship between their microscopic structure and dynamics. Explication of complex molecular systems can lead to their control and utilization. Participation of graduate students and postdoctoral students in all aspects of the research trains the next generation of first-rate scientists. Liquids and glasses are materials of high importance to industry, and students trained in these areas will compete extremely well in the high-technology job market.***