Putting the right spin on matters

The nuclear magnetic resonance (NMR) phenomenon has been of immense importance in several fields, in particular medical imaging and, as addressed here, chemistry. While in medical imaging the word "nuclear" has largely been dropped so as not to frighten patients, it is reassuring to see that NMR has been sensibly retained by the chemists as it is indeed a property of the nucleus of atoms and provides a powerful tool in the analysis of chemical structures.

This very clear and informative book limits its discussion primarily to liquid samples, concentrating on 1H and 13C (spin-half) nuclei.

The book is targeted at people familiar with the use of routine NMR methods for structure determination but "who wish to better their understanding of how NMR experiments work". Thus the purpose of this book is not to provide recipes to users of the method of how to perform experiments but to enable them to obtain a deeper understanding of what is going on.

At issue is to what extent the explanations provided are classical (spinning tops and the "vector model") or quantum mechanical. The author states that one cannot escape the need for quantum mechanics, but he succeeds in introducing these concepts gently (unlike a number of other well-known textbooks) without creating a barrier to those readers who might find such concepts, when introduced too rapidly, a major obstacle.

Indeed, the great strength of James Keeler's book is its clarity, and the way in which the explanations of the processes involved are introduced gradually. A deep mathematical understanding is not required (and a mathematical appendix is provided).

The development of the topics included in the book starts from the basic NMR experiment, a clear explanation of energy levels and the related spectra, pulse generation, product operators, the Fourier transform and data processing, an introduction to relevant quantum mechanical notions, leading up to an elegant presentation of two-dimensional NMR experiments.

Additional material in the book includes a deeper discussion of relaxation, the nuclear Oberhausen effect (NOE), coherence selection (including Cyclops, Cosy, Noesy and some of the other curiously named pulse sequences).

The book concludes with a very helpful practical chapter, entitled "How the spectrometer works", describing the equipment itself. There is an accompanying website that contains a solutions manual and copies of the illustrations in downloadable format.

Keeler's text is highly recommended to users of NMR spectroscopy who wish to gain a deeper understanding of the processes involved.

Andrew Todd-Pokropek is professor of medical physics and bioengineering, University College London.