Single Molecule Chemistry and Physics: An Introduction , C. Wang and C. Bai , Springer, New York, 2006. $119.00 (303 pp.). ISBN 978-3-540-25369-3
Chen Wang and Chunli Bai’s Single Molecule Chemistry and Physics: An Introduction is an ambitious attempt to review the wide variety of experimental techniques applied to studies of single molecules. In the introduction the authors state that they will refer readers to the original papers for details of the experimental methods. Their intent is to focus on what has been learned from those studies and on where future developments may lead. The extent to which Wang and Bai succeed is mixed. Their expertise in scanning probe microscopy is evident in the breadth, depth, completeness, and correctness of their coverage. In general, they do a good job on SPM, but not nearly as well on the optical techniques.
Although the book contains many distracting grammatical problems, they rarely interfere with the meaning of the text. Many of the sentences are simply clumsy, and inappropriate word choice and the lack of subject-verb agreement are rampant. In some cases the word choice is not just inappropriate but wrong. On page 1, for instance, Wang and Bai refer to “molecules laying on surfaces.” Granted, English is not their first language, so better editing on the part of the publisher would have been appreciated.
Chapters 2 through 6 are reasonably well organized and clear, and they provide a good summary of what has been done and what can be done with a number of techniques on a variety of molecular systems. Chapters 2 through 4 focus on scanning tunneling microscopy, the oldest and best-developed single-molecule technique. Chapter 2 summarizes the principles of electron tunneling and focuses on STM in particular. The chapter is a difficult read for nonexperts, as it contains many equations without much explanation, and not all quantities are defined. For example, for the tunneling current, equations 2.4 and 2.5 contain the quantity Δs, which is never defined. Chapters 3 and 4 address applications of STM, chapter 5 gives an introduction to scanning force microscopy, and chapter 6 covers measurements of the forces between molecules or within polymers by atomic force microscopy and related techniques and by the optical tweezers technique.
Chapter 7 reviews studies of single-molecule electrical conductivity. The chapter is brief; it summarizes some results on conductance through mono-layers and single molecules and also describes a few single-molecule devices, but it gives little perspective on the fascinating experimental and theoretical issues surrounding this rapidly evolving field.
The final chapters, 8 through 10, on optical and Raman spectroscopies are much weaker than the others. They read like an ambitious literature review by a diligent yet inexperienced student. Discussion of any given experiment is limited to a few sentences. The authors offer very little critical analysis or discussion of the importance of any of the studies, nor do they commit much effort to placing them in a broader context. The order of the material within a chapter is neither chronological nor selected in any other obvious way. Chapter 10, on surface-enhanced Raman spectroscopy, is particularly disappointing. After a brief introduction to Raman scattering and surface enhancement, the chapter launches into a list of briefly described results with little explanation or analysis and with references that do not seem to be in any particular order.
Measurements of single molecules involve probing physical and chemical properties at a level of detail often obscured by ensemble averaging in traditional bulk measurements. Single-molecule measurements provide the clearest experimental comparison with theory, which typically describes the behavior of an individual molecule interacting with its environment. Most of the other available books on single-molecule measurements are edited collections of articles. Such a format allows each topic to be addressed by an expert, but it inevitably introduces some repetition, gaps in coverage, and heterogeneity in style, level, notation, and point of view. Edited volumes can be good reference sources, but they are rarely useful as textbooks. The few existing monographs on the subject, such as Handbook of Single Molecule Fluorescence Spectroscopy (Oxford U. Press, 2006) by Alastair Smith, Christopher Gell, and David Brockwell and Selective Spectroscopy of Single Molecules (Springer, 2006) by Igor Osad’ko, are much narrower in scope than the edited volumes.
Bai and Wang aimed high when they attempted to cover a broad range of single-molecule measurements in one monograph. Unfortunately, the result is not fully successful. Much of the coverage in Single Molecule Chemistry and Physics is too terse to provide a useful learning resource for graduate students or postdocs. And in this rapidly evolving field, the book is already somewhat out of date as a reference.
