MAGNETIC RESONANCE IN CHEMISTRYMagn. Reson. Chem. 2002; 40: S2Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/mrc.1139

Guest Editor’s Foreword: NMR and Diffusion

It is now just over 50 years since Erwin Hahn’s first paper on the phenomenon of the spin echo, in whichhe noted that the formation of echoes could be disrupted by diffusion. This proved to be a significantobservation, paving the way for a whole range of experimental methods to investigate both coherent andincoherent molecular motion. NMR can now measure the velocities of motions slower than continentaldrift, and detect average molecular displacements of the order of nanometres. One spectacular, and surelyunanticipated, application of Hahn’s observation has been the development of techniques for mapping themotion of blood and other fluids in the human body.

While the study of diffusion by NMR has made many important contributions over the years, untilrecently it was the province largely of those specialists with the skills needed to construct and maintain thespecial apparatus required. The recognition that pulsed field gradients can greatly improve the speed andspectral quality of multidimensional NMR, coupled with developments such as actively shielded gradientcoils, has now led to pulsed field gradient capabilities becoming almost universal on modern routine highresolution spectrometers. As a result, diffusion measurements on all but the largest species are now withinthe scope of most NMR laboratories, and there has been a blossoming both of chemical applications ofNMR diffusion measurements, and of new techniques for making such measurements. This special issueof the journal Magnetic Resonance in Chemistry illustrates both the very wide range of systems that can nowprofitably be studied, from gases through natural products and biomolecules to synthetic polymers andcolloids, and the great variety of instrumental and data processing techniques which can contribute to ourunderstanding and exploitation of the phenomenon of diffusion.

Gareth MorrisUniversity of Manchester

Manchester, UK

Copyright 2002 John Wiley & Sons, Ltd.