Review - Modern Raman Spectroscopy: A Practical Approach

Review - Modern Raman Spectroscopy: A Practical Approach. Michael D. Morris. Anal. Chem. , 2006, 78 (1), pp 33–33. DOI: 10.1021/ac069338n. Publicati...
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Modern Raman Spectroscopy: A Practical Approach Ewen Smith and Geoffrey Dent John Wiley & Sons, 2005, 210 pp, $90,


he authors of this book are experienced Raman spectroscopists whose joint expertise covers a fairly wide range of topics. They attempted to write an introduction to Raman scattering and its applications for nonspecialists. They succeed in some chapters and are less successful in covering one or two areas. The authors do not say who the nonspecialists are, but they assume a background in chemistry at the level of undergraduate physical chemistry. The book surveys theory, instrumentation and sampling, and applications, with special emphasis given to the resonance Raman effect, surface enhancement, and a few highly specialized methods, mostly involving pulsed lasers. Smith and Dent begin with an introductory description of Raman scattering by small molecules. The emphasis is on a qualitative discussion of scattering, with examples based on symmetry considerations for small molecules and a segue into group frequencies for organic compounds. A little more detail is presented than in upper-division undergraduate texts, but the level is similar. The authors return to theory later, with a much more sophisticated treatment of scattering. After a discussion of scattering that is correct but somewhat roundabout, the authors describe the polarizability tensor © 2006 AMERICAN CHEMICAL SOCIETY

and its implications and then present a highly abbreviated discussion of the quantum mechanical approach to scattering intensity. The Kramer–Heisenberg–Dirac equation is used as the starting point of a discussion of Raman intensities, with little explanation of the terminology of the equation or the concepts that it represents. Depending on the rigor of one’s physical chemistry courses, this section may or may not be comprehensible. Lattice modes are briefly and accurately discussed, although with inadequate connection to real structures. An entire chapter is devoted to resonance enhancement. It is a well-done and comprehensive treatment. The chapter on experimental techniques is disappointing. Too much ground is covered, and some egregious errors exist. The description of notch filters is wrong, for example. The notch filter reflects laser light, rather than absorbing it. CCDs are not inefficient in the visible, as claimed. The peak quantum efficiency is close to 90%. Only the N-around-1 fiber-optic probe is discussed, although the filtered 2-fiber designs are at least as widely used. On the bright side, detailed and useful information on the handling of powders and liquids is presented. The technique discussion has two serious drawbacks. First, the treatment of instrument calibration is superficial. Indene is recommended for wavenumber scale calibration, but no table of indene Raman shifts is presented. No discussion is given of the role of discharge lamps, which are widely used to calibrate the Raman shift scale. Although multivariate calibration is mentioned, commonly used techniques and their shortcomings are not discussed. The same is true of smoothing, a widely used but statistically dubious procedure. The chapter on surface-enhanced Raman spectroscopy (SERS) is a high point. It is detailed and reasonably upto-date. There has been a recent resurgence of interest in SERS, driven by potential homeland security and biomedical applications, development of reproducible substrates, and establishment of satisfactory protocols for working with less-reproducible ones. The novice would do well by starting here.

The applications survey chapter reflects the authors’ interests, as is inevitable. It is impossible to cover the entire range of applications of Raman spectroscopy in fewer than 40 pages. Smith and Dent have done a good job of briefly discussing a cross-section of applications of interest to chemists. A good selection of references to the primary literature serves to guide the interested reader to more detailed coverage. In the concluding chapter, some advanced but eclectic methods are briefly discussed. Small spectrographs, near-field Raman microscopy, and time-resolved and nonlinear spectroscopy are included, as are Raman optical activity and UVexcited resonance enhancement. All are useful, but most have been practiced by relatively few laboratories, either because the range of applications is limited or because the equipment is too expensive and complex for widespread adoption. Despite its shortcomings, this volume is a balanced introduction to Raman spectroscopy. It is a useful starting point for the chemist who is just entering the field and does not want or need the more detailed books that are available. Reviewed by Michael D. Morris, University of Michigan

b Encyclopedia of Chromatography, Second Edition Edited by Jack Cazes Taylor & Francis, 2005, 1800 pp, $535, This two-volume set contains ~370 entries written by ~270 authors. The size of the entries varies from 2 to 10 pages; each includes references and/or suggested reading. Some of the entries are Adsorption Chromatography, Affinity Chromatography of Cells, Detection in Countercurrent Chromatography, Field-Flow Fractionation Data Treatment, HPLC Column Maintenance, LC/MS, Molecular Interactions in GC, Polymer Degradation in GPC/SEC, Rotation Locular Countercurrent Chromatography, and TLC of Synthetic Dyes.

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