Oxford University Press, 2010 280 pages, $65.00 ISBN13: 978-0-19-958381-2 ISBN10: 0-19-958381-1
This book is the 16th installment in the series of monographs on crystallography by the International Union of Crystallography (IUCr). Its author, T.R. Welberry of the Australian National University, is well known to the worldwide crystallography community as a co-editor of Acta Crystallographica B and a long-time leader in the IUCr. Moreover, Welberry is widely considered as one of the experts in the theory and application of diffuse x-ray scattering to problems in modern chemical crystallography. Given the paucity of treatments of diffuse scattering in the x-ray literature, this volume has the potential for serving as an important addition to the libraries of chemical crystallographers everywhere.
The compact book (266 pages) is divided into three sections: Experiment, Disorder Models, and Examples of Real Disordered Systems. The first of these is only 17 pages, and although the author explicitly states that a discussion of laboratory methods is not a major thrust of the book, the experimentally inclined reader is likely to wish for more information than is presented here. In contrast, the main focus of the book is set in the section on Disorder Models, where Welberry establishes the theoretical basis for structures that generate diffuse scattering. Starting with the mathematics of disorder in one dimension, increasingly complex models are considered in turn. Mathematically challenged readers would be well-advised to review books on conditional probabilities, Markov chains, and Ising models prior to reading Welberry’s work, since the level of his treatment is likely to be found to be fairly advanced for the average chemical crystallographer.
Throughout this section Welberry presents numerous examples where illustrations of real-space disordered structures are shown side-by-side with their resultant calculated reciprocal-space patterns. Such figures are most welcome, of course—but in the cases such as Figure 3.3 where 10 pairs of patterns (20 examples total!) are presented on the same page, the resultant size reduction makes careful study all but impossible. A preferable editorial choice might have been to expand such figures over a two-page spread to allow the individual panels to be viewed with greater ease. In cases where the real and reciprocal-space representations are presented in an easy-to-view format (such as in Figures 6.8 and 6.9), the reader has the opportunity to fully understand the impact of real-space structure on the reciprocal-space diffraction pattern.
The remaining, and major, portion of the book consists of a series of examples—many from Welberry’s own extensive published research—where studies of diffuse scattering have generated new insights into the structure of both organic and inorganic crystals. The breadth of such applications is truly stunning and should convince even the most novice reader of the power of diffuse scattering measurements. The wealth of structural information that is evident from these analyses signals the prize that waits at the end of the rainbow: the crystallographer who is willing to work through the needed probability theory will be rewarded with an appreciation for the information that is to be found in the diffuse scattering.
Welberry’s book is not for the faint of heart: junior readers may be scared off by the mathematical rigor that is demanded in the section on Disorder Models. That being said, this book will be a valuable addition to the libraries of all crystallographers as it displays in meticulous detail the information that is available so long as one chooses to look elsewhere in reciprocal space and beyond the standard Bragg reflections.
Reviewer: Richard Matyiof the College of Nanoscale Science and Engineering, University at Albany–SUNY.
