Dynamics of Molecules in Complex Molecular Materials

本项目的目的是研究复杂凝聚态分子系统中的动力学和分子间相互作用。将研究各种各样的材料，包括玻璃、过冷液体、液晶、氢键团簇、胶束、反胶束、聚合物和聚合物胶束。复杂分子系统中的动力学可以跨越广泛的时间尺度。因此，这些实验针对的是足够广泛的时间范围内的观测，以提供动力学的详细图景。超快红外振动回波实验和红外泵浦-探测实验将被用来研究振动动力学，它反映了嵌入振动振子的介质的动力学，以及耦合从非均匀系统中提取的退相动力学的分子间相互作用的性质，因此不能用常规的线性光谱学来研究。振动回声研究将扩展到包括其他振动相干实验，包括受激发的振动回波和各种类型的二维振动回波实验。受激发的振动回波将提供更长时间尺度的动力学信息，即振动光谱扩散。第一个二维振动回波实验--振动回声光谱学--在上一次资助期间得到了演示。这项技术将进一步发展，它提供了一种抑制振动光谱中不需要的背景吸收的方法。还将开展两个时间二维实验，以探索不同机械自由度之间的耦合。振动回波实验和相关的非线性振动相干实验将用于研究高温玻璃、过冷液体、反胶束核心中的水、溶剂中水和醇的氢键团簇、纯液体和蛋白质中的动力学。瞬变光栅光学克尔效应实验、外差放大光学克尔效应实验和一种新的方法--密度诱导外差放大转动动力学--将被应用于复杂分子系统动力学的研究，研究范围从几十飞秒到毫秒甚至更长。在本授权期内的工作表明，这些技术的组合提供了巨大的信号和时间动态范围，可以从根本上提供关于复杂系统性质的新信息。这些技术将应用于过冷液体、胶束、聚合物胶束、聚合物和液体晶体。这项研究的重点是复杂的凝聚体系统，如过冷液体、胶束、聚合物和液体晶体，以及光学平板显示器和结构材料等应用的材料加工的优化。

The aim of this project is to investigate the dynamics and intermolecular interactions in complex condensed matter molecular systems. A wide variety of materials will be studied, including glasses, supercooled liquids, liquid crystals, hydrogen bonded clusters, micelles, reverse micelles, polymers, and polymer micelles. Cynamics in complex molecular systems can span a wide range of time scales. Therefore, the experiments ae directed toward observations over a sufficiently wide range of times to provide a detailed picture of the dynamics. Ultrafast infrared vibrational echo experiments combined with infrared pump-probe experiments will be used to study vibrational dynamics which reflect the dynamics of the medium in which the vibrational oscillator is embedded and the nature of the intermolecular interactions that couple dephasing dynamics to be extracted from systems that are inhomogeneous, and, therefore, cannot be studied with convention linear spectroscopy. The vibrational echo studies will be extended to include other vibrational coherence experiments including stimulated vibrational echoes and various types of two dimensional vibrational echo experiments. Stimulated vibrational echoes will provide information on longer time scale dynamics, i.e., vibrational spectral diffusion. The first tow-dimensional vibrational echo experiments, Vibrational Echo Spectroscopy, was demonstrated in the previous grant period. This technique, which provides a method for the suppression of unwanted background absorptions in a vibrational spectrum, will be developed further. Two time 2D experiments that probe the coupling between different mechanical degrees of freedom will also be developed. Vibrational echo experiments, and the related non-linear vibrational coherence experiments, will be used to study dynamics in high temperature glass, supercooled liquids, water in the core of reverse micelles, hydrogen bonded clusters of water and alcohols in solvents, pure liquids, and proteins. Transient grating optical Kerr effect experiments, heterodyne amplified optical Kerr effect experiments, and a new method, density induced heterodyne amplified rotational dynamics, will be applied to the study of dynamics in complex molecular systems over vast ranges of time, from tens of femtoseconds to milliseconds and longer, Work during the current grant period has shown that a combination of these techniques, which provide tremendous dynamic range in signal and time, can provide fundamentally new information about the nature of complex systems. The techniques will be applied to supercooled liquids, micelles, polymer micelles, polymers, and liquids crystals.The emphasis in this study is on complex condensed matter systems such as supercooled liquids, micelles, polymer micelles, polymers, and liquids crystals and on the optimization of materials processing for applications such as optical flat panel desplay devices and structural materials.