Experimental Studies of the Dynamic Structure of Liquids

Jiri Jonas获得了The Theoretical and Computational Chemistry Program的资助，继续利用NMR和激光拉曼光谱对液体的动态结构进行实验研究。这项研究的主要目的是研究高压和密闭区域内的液体。高压下液体的高分辨率核磁共振被用于分离密度和温度对动态过程（如自扩散和剪切粘度）的影响。最近在溶胶-凝胶法制备多孔硅玻璃方面的工作已经导致了对玻璃中液体的核磁共振和拉曼光谱的研究，这些液体的孔径从10 A到200 A。主要研究方向包括：1)在接近玻璃化转变温度的液体中，对流体力学Stokes-Einstein和Debye方程在分子水平上的适用性进行NMR研究；2)处理约束效应对液体角动量行为的核磁共振实验；3)密闭液体中构象异构化的核磁共振研究；4)约束效应对液体振动和重定向弛豫的拉曼研究；5)核磁共振研究压力对酰胺和聚酰胺水溶液中氢交换的影响。通过对高压液体的核磁共振研究，在原子和分子水平上获得关于液体的新信息，将有助于了解润滑剂的功能。液体在受限几何结构中的研究在催化、色谱、膜分离和地质构造中的液体渗透性等许多领域都有技术应用。

Jiri Jonas is supported by a grant from The Theoretical and Computational Chemistry Program to continue his research in experimental studies of the dynamic structure of liquids using NMR and laser Raman spectroscopy. The major thrust of the research is to study liquids at high pressures and in confined regions. High resolution NMR of liquids under high pressures is being used to separate the effects of density and temperature on dynamical processes such as self-diffusion and shear viscosities. Recent work on the preparation of porous silica glasses by sol-gel processes have led to studies of both NMR and Raman spectra of liquids confined in glasses with well defined pore sizes from 10 A to 200 A. The main research directions to be explored include: 1) NMR studies of the applicability of the hydrodynamic Stokes-Einstein and Debye equations at the molecular level in liquids near their glass transition temperature; 2) NMR experiments dealing with confinement effects on angular momentum behavior in liquids; 3) NMR study of conformational isomerization in confined liquids; 4) Raman studies of confinement effects on vibrational and reorientational relaxation in liquids; and 5) NMR study of the pressure effects on hydrogen exchange in aqueous solutions of amides and polyamides. New information on liquids at the atomic and molecular level obtained through NMR studies of liquids at high pressure will help in understanding the function of lubricants. The studies of liquids in confined geometries has technological applications in many fields including catalysis, chromatography, membrane separations, and liquid permeability in geological formations.