Brownian motion and its effects in NMR chemical exchange and relaxation in liquids

At any instant, the magnetic dipolar moments or electric quadrupolar moments of atomic nuclei in a liquid experience interactions that depend on local structural parameters. Because such interactions depend on the distance and orientation of nearby magnetic dipole moments and electric charges, Brownian motions are reflected in the NMR spectra and relaxation times. We can use mathematical models based on our physical and chemical knowledge and intuition to help us interpret NMR data in terms of structure acid motions. With proper experiments, we can use this approach to investigate molecular motions, structure, and interactions in liquids; molecular orientations at surfaces; and the range of interfacial order in heterogeneous materials, such as gels and biological tissue. (C) 1996 John Wiley & Sons, Inc.