Dynamics of Electronically Excited States. Models for Chemical Reactivity

实验物理化学计划支持大卫普拉特从 匹兹堡大学继续研究电子 货车范德华配合物旋转分辨光谱 分子束中的荧光激发光谱。 这些目标是 a）确定分子间势能面， 处于最低两个单重电子态的苯-水络合物，B） 确定溶剂诱导的肽结构变化 c）研究了络合物的影响 分子内弛豫过程的研究 化学反应动力学的构象控制。 力场和AB 还将进行初始计算。 更全球化的目标 这些研究的重点是研究一个人从 量子力学的经典极限，通过研究较大的非对称 转子具有较小的能级间距通过激励深入到 紫外线 物质在许多长度尺度上表现出结构的层次， 在一个尺度上的“组件”在下一个尺度上变成了“组成部分”。 在 这种层次结构，货车范德华相互作用和氢键作用 特别突出的作用，导致孤立的聚集， 将分子组装成具有特征的组成部分 宏观的液相和固相。 氢键也表现为 在复杂的三维结构中， 蛋白质、基因、膜和其他大分子成分， 生活系统 因此，重要的是要确定和描述 基本的“超分子”单位，形成之间的桥梁， 微观和宏观领域。 这就是这些的目的。 问题研究

The Experimental Physical Chemistry Program supports David Pratt from the University of Pittsburgh in his continuing studies of the electronic spectroscopy of van der Waals complexes using rotationally-resolved fluorescence excitation spectroscopy in molecular beams. The goals are to a) determine the intermolecular potential energy surfaces of the benzene-water complex in the lowest two singlet electronic states, b) determine the solvent-induced changes in the structure of the peptide bond in the formanilide-water complex, c) study the influence of complex formation on intramolecular relaxation processes, and 4) study conformational control of chemical reaction dynamics. Force field and ab initio calculations will also be carried out. The more global objective of these studies is to investigate the point at which one goes from the quantum mechanical to the classical limit, by studying larger asymmetric rotors with smaller energy level spacings via excitation deep into the ultraviolet. Matter exhibits a hierarchy of structures at many length scales, with `assemblies` at one scale becoming `component parts` at the next. In this hierarchy, van der Waals interactions and hydrogen bonding play particularly prominent roles, leading to the aggregation of isolated molecules into assemblies that become the characteristic component parts of macroscopic liquid and solid phases. Hydrogen bonding also appears as a ubiquitous feature in the complex three-dimensional structures of proteins, genes, membranes, and other macromolecular constituents of living systems. It is therefore important to identify and characterize the basic `supramolecular` units that form the bridge between the microscopic and macroscopic domains. This is the purpose of these studies.