Raman Spectroscopy L. Andrew Lyon, Christine D. Keating, Audrey P. Fox, Bonnie E. Baker, Lin He, Sheila R. Nicewarner, Shawn P. Mulvaney, and Michael J. Natan* Department of Chemistry, 152 Davey Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802 Review Contents Organization 341R Books, Periodicals, and Reviews 341R Instrumentation and Data Analysis 343R General Instrumentation 343R Remote Sensing 344R Microscopy/ Imaging 344R Applications 344R Theory 345R M aterials 345R Superconductors 346R Semiconductors 346R Carbonaceous Materials Including Fullerenes 346R Catalysts 347R Oxides, Glasses, Gels, and Clays 347R Molecules and Molecular Systems 347R Environmental Materials 347R Archeological Materials 347R Biological Materials 347R Polymers 348R Particles and Droplets 348R Raman Scattering at Surfaces 348R SERS Substrate Development/ Characterization 349R Matrixes for SERS 349R Characterization of SERS Substrates 349R SERS Methods 350R Applications of SERS 350R SERS Theory and Experimental Tests of Theory 351R Chemically Enhanced and Unenhanced Raman 351R Nonlinear Raman Techniques 351R Biological Applications of Raman 352R Proteins 352R Nucleic Acids 352R Lipids 353R Applications/ Diagnostics 353R Prospectus 353R Literature Cited 354R ORGANIZATION The period covered by this document is from the beginning of 1995 through late 1997. The most recent comprehensive review of this topic appeared in 1994 ( 1) and covered late 1991 through late 1993. Thus, there exists a gap in coverage of just over a year. It is hoped that this review is sufficiently comprehensive to incorporate important results first described in publications that appeared during that time period. With roughly 11 000 CAS citations to Raman over the last two years, this “awakening giant” ( 2) has apparently ended its slumber! This number is nearly double the 1994 figure and reflects several important trends. Clearly, the ready availability and relatively low cost of CCD cameras, notch filters, and compact, rugged lasers has made it easier to construct a Raman apparatus. Likewise, the purchase of packaged Raman spectrometers has been facili- tated by the creation of numerous companies selling stand-alone instruments. However, the main factor leading to the upsurge in Raman-related publications has been the worldwide explosion in materials science, with the accompanying need for materials characterization. In several respects, Raman is well-suited for this task. First, the ability to acquire vibrational data for a variety of nontransparent solidsssometimes under extreme conditionsssets it apart from infrared. Second, the development of Raman microscopy has made it possible to look at very small quantities of materials, or even domains within materials, with a resolution of a few square micrometers. Third, Raman is nondestructive. Finally, the use of UV and near-IR excitation sources has become commonplace, extending the window from which Raman scatter- ing can be observed. This review gives extensive coverage to materials characteriza- tion by Raman, to biological applications of Raman, and to surface- enhanced Raman scattering (SERS), because it is felt that these topics are of greatest importance to the analytical community. The review is organized into five parts. The first section covers books, periodicals, and reviews in a fairly comprehensive fashion. This is followed by sections on (i) instrumentation, methods, data analysis, and theory; (ii) materials; (iii) SERS and nonlinear Raman methods; and (iv) biological applications of Raman. None of these sections are comprehensive, focusing rather on research high- lights and on examples that illustrate breadth within a particular area. BOOKS, PERIODICALS, AND REVIEWS Several useful books were published during this period. These include a new two-volume edition of Nakamoto’s classic book on infrared and Raman spectra of coordination compounds, with one self-contained volume devoted to basic theory and applications to small molecules, and the second on larger molecule applications in coordination, organometallic, and bioinorganic chemistry ( 3, 4). A four-volume handbook on IR and Raman was published ( 5), as were the proceedings from the Fourteenth and Fifteenth International Conferences on Raman Spectroscopy ( 6, 7). Texts on introductory Raman ( 8), IR and Raman methods ( 9), Raman and IR in biology and biochemistry ( 10), modern techniques ( 11), and Raman microscopy also appeared ( 12). The latter had chapters on basic aspects of Raman microscopy, as well as chapters on applications in materials science, in earth, planetary, and environmental sciences, in biology, in medicine, and in forensic science. The proceedings of a conference on the spectroscopy of biological molecules was published, with the Anal. Chem. 1998, 70, 341R-361R S0003-2700(98)00021-3 CCC: $15.00 © 1998 American Chemical Society Analytical Chemistry, Vol. 70, No. 12, June 15, 1998 341R Published on Web 05/09/1998