Experimental Studies of the Dynamic Structure of Liquids

Jiri Jonas得到了理论和计算化学计划的资助，继续利用核磁共振和激光拉曼光谱对液体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受限区域中的液体。高压下液体的高分辨率核磁共振被用来分离密度和温度对动态过程的影响，如自扩散和剪切粘度。近年来，在溶胶-凝胶法制备多孔二氧化硅玻璃的研究中，主要研究了孔径为10A~200A的玻璃中液体的核磁共振和拉曼光谱。主要研究方向包括：1)在分子水平上研究流体动力学的Stokes-Einstein方程和德拜方程在液体玻璃化转变温度附近的适用性；2)核磁共振实验研究限制对液体角动量行为的影响；3)核磁共振研究受限液体中的构象异构化；4)拉曼研究限制效应对液体中振动和重定向弛豫的影响；5)核磁共振研究了压力对酰胺和聚酰胺水溶液中氢交换的影响。通过对高压下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，这将有助于理解润滑剂的功能。受限几何中液体的研究在许多领域都有技术应用，包括催化、层析、膜分离和地质地层中的液体渗透性。

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.