Dynamics in Condensed Matter Systems

摘要9322504费耶尔这项研究利用多时间尺度的非线性实验考察了各种凝聚态系统中的快速动力学以及动力学与局域结构的关系。被检查的材料包括低温玻璃、玻璃化转变附近的高温玻璃、玻璃形成液体和玻璃化转变、以及具有局部结构的液体，如液晶和聚合物熔体。出于组织目的，该提案分为三个部分：(A)凝聚态系统中的PSEC振动光子回波；(B)低温玻璃、玻璃和玻璃相变附近液体的光学相干研究；以及(C)复杂液体的动力学：玻璃形成液体、聚合物熔体和液晶，通过FSEC瞬变光栅实验进行探测。(A)中的信息将提供：1)检查分子的振动自由度与其动态环境的相互作用的直接方法，以及2)对玻璃和液体中的动力学以及分子间动态相互作用的详细见解。在(B)中，绘制了液体和玻璃的波动率分布图。这些实验考察了在广泛的温度和时间范围内的均匀退相和光谱扩散。小节(C)包括审查局部结构对复杂液体动力学的作用。这些实验的时间跨度从几十毫秒到数百毫微秒甚至更长。%使用基于激光的技术，这项建议解决了一些基本问题，涉及微观层面上的动力学和结构的相互作用。被检查的材料包括低温玻璃、玻璃化转变附近的高温玻璃、玻璃形成液体和玻璃化转变、以及具有局部结构的液体，如液晶和聚合物熔体。需要回答的问题如下。分子凝聚态系统中的动力学发生在什么时间尺度上？介质的动力学如何影响嵌入分子的机械和电子自由度？局部结构如何决定分子水平上发生的动力学的性质？能量流入和流出分子的时间尺度和路径是什么？玻璃、液体和晶体性质的差异如何影响动力学过程？结构液体，例如液晶、聚合物熔体和玻璃形成液体中的动力学与简单液体中的动力学有何不同？

Abstract 9322504 Fayer This research examines fast dynamics and the relationship of dynamics to local structure in a variety of condensed matter systems using multiple time scale non-linear experiments. The materials to be examined include low temperature glasses, high temperature glasses near the glass transition, glass forming liquids and the glass transition, and liquids with local structure such as liquid crystals and polymer melts. The proposal is divided into three subsections for organizational purposes: (A) Psec Vibrational Photon Echoes in Condensed Matter Systems; (B) Optical Coherence Studies of Low Temperature Glasses and Glasses and Liquids Near the Glass Transition; and (C) Dynamics of Complex Liquids: Glass Forming Liquids, Polymer Melts, and Liquid Crystals Probed with Fsec Transient Grating Experiments. The information in (A) will provide: 1) a direct method for examining the interactions of a molecule's vibrational degrees of freedom with its dynamic environment, and 2) detailed insights into dynamics in glasses and liquids and dynamical intermolecular interactions. In (B), fluctuation rate distributions are mapped out for liquids and glasses. The experiments examine homogeneous dephasing and spectral diffusion over a wide range of temperatures and time scales. The subsection (C) includes examination of the role of local structure on the dynamics of complex liquids. The experiments span time scales of tens of fsec to hundreds of nsec and longer. %%% Using laser-based techniques, this proposal addresses a number of basic questions concerning the interplay of dynamics and structure at the microscopic level. The materials to be examined include low temperature glasses, high temperature glasses near the glass transition, glass forming liquids and the glass transition, and liquids with local structure such as liquid crystals and polymer melts. The questions to be answered are as follows. On what time scales do dynamics in molecular condensed matter systems occur? How do dynamics of a medium influence the mechanical and electronic degrees of freedom of an embedded molecule? How does local structure determine the nature of dynamics occurring on a molecular level? What are the time scales and pathways for the flow of energy into and out of molecules? How do differences in the nature of glasses, liquids, and crystals influence dynamical processes? How do dynamics in structured liquids, e. g., liquid crystals, in polymer melts, and in glass forming liquids differ from dynamics in simple liquids?