Raman Spectroscopy Of Gases And Liquids

The Raman effect is a most useful tool for the study of molecular vibrations and molecular structure. Information about the structure and symmetry of molecules, as well as about their vibrational energies can be obtained to a reasonable degree of satisfaction from their infrared and Raman vibrational spectra. The body of knowl edqe of the vibrational infrared and Raman spectra of molecules is immense and is now so well organized and understood that it is found to be represented in any stan dard upper level undergraduate curriculum in chemistry. The rotational energies of a molecule and quantitative details about its structure can only be obtained through the techniques of microwave, and high-resolution infrared and Raman spectroscopy of low pressure gases and vapors. The results of such investigations are of interest . not only to the academic scientists, but also to scientists and engineers who are active in applied fields of chemistry and physics, as well as the atmospheric sciences. This book deals with basic investigations of the Raman scattering of light by gases, with some attention also being given to liquid substances. After a brief in troductory chapter that delineates the historical development of Raman spectroscopy of gases, high-resolution rotation-vibrational and pure rotational Raman spectros copy is described in Chapters 2 and 3. The all-important intensity parameter, the Raman scattering cross section, is treated in Chapter 4, while the broadening of Raman lines due to the effects of intermolecular forces is taken up in Chapter 5.

This book describes a simple yet innovative method for performing Raman spectroscopy of samples submerged under liquid nitrogen. While Raman spectroscopy has proven to be a powerful tool for the characterization of the structure of matter in the gaseous, liquid, and solid phases, one major difficulty in its application has been laser damage to the material under investigation, especially for biological samples. This book demonstrates how immersion of the sample in liquid nitrogen protects the sample from thermal degradation and oxidation at high incident laser power and allows improvements in sensitivity and spectral resolution over room-temperature Raman spectroscopy, leading to the so-called RUN (Raman Spectroscopy Under liquid Nitrogen) technique. Cooling to liquid nitrogen temperature also allows the selection of the lowest energy molecular conformation for molecules which may have many low energy conformers. In addition, the presence of liquid nitrogen over a roughened surface improves the sensitivity of Surface Enhanced Raman Spectroscopy (SERS), enabling the closely related SERSUN (Surface-Enhanced Raman Spectroscopy Under liquid Nitrogen) technique. This book starts with the theoretical and experimental basics of Raman and polarized Raman spectroscopy, before moving on to detailed descriptions of RUN and SERSUN. Room temperature and RUN spectra are provided for over fifty molecules.

This volume sets out to draw together the essential expertise which will provide a technical guide to the practice of Raman spectroscopy. The text deals exc1usively with spontaneous Raman spectroscopy and inc1udes some aspects of Resonance Raman spectroscopy. Chapter I sets out the essential theoretical framework using a simple c1assical approach and deals with the rudiments of polarizability. Many of these theoretical points are further developed in Chap. 2 where the scattering and polarization consequences of various sampling geometries and collection optics, on gaseous, liquid, single crystal and thin film methods are detailed. The relative advantages and disadvantages of the wide variety of hardware now available to the Raman spectroscopist are discussed in Chap. 3. Important calibration data is pr. esented in Chap. 4 along with an account of datä analysis techniques, inc1uding signal enhancement methods. Chapter 5 describes some of the techniques and cell designs that have been successfully used to study sampies under extreme conditions and Chap. 6 deals with the rapidly growing technique of Raman microscopy, providing a wide range of application examples and experimental advice. We recognise the difficulty in covering all aspects of Raman spectroscopy in a single volume and a section on further reading, representing what we feel are amongst the more informative references, at the time of publication, is provided for additional detail. Our hope is that Practical Raman Spectroscopy will help to provide a source of on-hand technical support and data for the practising Raman spectroscopist in the laboratory.

This work covers principles of Raman theory, analysis, instrumentation, and measurement, specifying up-to-the-minute benefits of Raman spectroscopy in a variety of industrial and academic fields, and how to cultivate growth in new disciplines. It contains case studies that illustrate current techniques in data extraction and analysis, as well as over 500 drawings and photographs that clarify and reinforce critical text material. The authors discuss Raman spectra of gases; Raman spectroscopy applied to crystals, applications to gemology, in vivo Raman spectroscopy, applications in forensic science, and collectivity of vibrational modes, among many other topics.

The Laser Raman Workshop on the r"eas urement of Gas Properti es i sone of aseries of occasional meetings organized in an informal workshop format through the stimulation of Project SQUID, Office of Naval Research. This workshop is the second to be organized on gas-phase applications of Raman scattering. Both Raman workshops were supported by Project SQUID, ONR, and the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base. The first Raman Workshop was held at the AVCO Everett Research Laboratory, Everett, Massachusetts, with their co-sponsorship in January 1972 under the chairmanship of D. A. Leonard. The present meeting was co-sponsored by the General Electric Research and Development Center, and held at their facility in Schenectady, New York. We are grateful to Project SQUID, AFAPL, and GE for their generous financial support of this Workshop, and to Project SQUID for underwriting the publication costs of the Proceedings. As is always the case for successful meetings, many people contributed substantially to the organization and execution of this workshop. Professor Robert Goulard supported, aided, and encouraged us in the most helpful ways, and we are indebted to him. We received further valuable support and assistance from Dr. Ralph Roberts, Director, and Mr. James R. Patton, Jr., of the Power Branch, Office of Naval Research; from Dr. William H. Heiser, Chief Scientist of the Aero Propulsion Laboratory; and from Dr. James M.

A review of the fundamental concepts and models which underpin the spectroscopic study of gases and liquids, first published in 1994.