NMR (Nuclear Magnetic Resonance) Spectroscopy at High Pressure

摘要

The field of NMR spectroscopy at high pressure has been discussed in several recent review articles. It has been well documented that for providing rigorous experimental tests of current theoretical models of liquids, one has to use pressure as an experimental parameter and separate the effects of density and temperature on molecular motions and interactions. This article will discuss our recent developments in the field of NMR FT spectroscopy at high pressure. Two illustrative examples of this specific technique are given. First, the I3C NMR experiments of rhodium carbonyl clusters under high pressures of CO/H2 illustrate the promising future of the high resolution, high pressure FT NMR in studies of homogeneous catalytic processes. Second example deals with the investigation of the pressure effects on conformational inversion in cyclohexane. This represents the first experiment which has shown conclusively the importance of the pressure dependent collisional contribution to isomerization reactions as predicted by recent stochastic models of isomerization dynamics in liquids. In order to illustrate the scope and range of high pressure NMR experiments, the next part of the article discusses our recent results on relaxation and transport behavior of compressed supercritical water. The article finishes with a brief account of application of high pressure NMR to studies of the dynamic structure of various disordered systems.