Raman Spectroscopy of Gases and Liquids

ISBN-13: 9783642812811 / Angielski / Miękka / 2011 / 320 str.

A. Weber

Opis

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.

Spis treści

1. Introduction.- References.- 2. High-Resolution Rotation-Vibrational Raman Spectroscopy.- 2.1 Theory.- 2.1.1 Intensity Expressions.- 2.1.2 Selection Rules.- 2.1.3 The Vibrational Matrix Element.- 2.1.4 Linear Molecules.- 2.1.5 Symmetric Top Molecules.- 2.1.6 Asymmetric Top Molecules.- 2.1.7 Spherical Top Molecules.- 2.1.8 Comparison with the Theory of Infrared Spectra.- 2.2 Experimental Technique.- 2.2.1 General Features of Instrumentation and Technique.- 2.2.2 Details of Present Instruments.- 2.2.3 Comparison to Infrared Experimental Techniques.- 2.3 Results.- 2.3.1 General Remarks.- 2.3.2 Linear Molecules.- 2.3.3 C3v Molecules.- 2.3.4 Other Symmetric Top Molecules.- 2.3.5 Asymmetric Top Molecules.- 2.3.6 Spherical Top Molecules.- 2.3.7 Conclusion.- References.- 3. High-Resolution Rotational Raman Spectra of Gases.- 3.1 Instrumentation and Techniques.- 3.1.1 The Raman Source Unit.- a) The Laser System.- b) The Scattering Cell.- c) The Illuminating Optics.- d) The Transfer Optics.- 3.1.2 Filters.- 3.1.3 The Spectrograph.- 3.1.4 Recording Materials.- 3.1.5 Wavelength Standards.- 3.1.6 Determination of Raman Shifts.- 3.1.7 Photoelectric Spectrometers.- 3.1.8 Interferometric Techniques.- 3.2 Observed Rotational Spectra.- 3.2.1 Diatomic Molecules.- 3.2.2 Linear Polyatomic Molecules.- 3.2.3 Symmetric Top Molecules.- 3.2.4 Asymmetric Top Molecules.- 3.2.5 “Forbidden” Pure Rotational Spectra.- a) Spherical Top Molecules — Td Symmetry.- b) Symmetric Top Molecules — C3V Symmetry.- 3.3 Summary.- References.- 4. Raman Scattering Cross Sections in Gases and Liquids.- 4.1 Raman Scattering Cross Sections in Gases.- 4.1.1 Theoretical Considerations.- 4.1.2 Determination of the Absolute Scattering Cross Section of Nitrogen.- 4.1.3 Measurement of Relative Scattering Cross Sections.- a) Experimental Procedure.- b) Results.- c) Influence of the Resonance Raman Effect.- 4.2 Raman Scattering Cross Sections in Liquids.- 4.2.1 Internal Field Effect and Intermolecular Interactions.- 4.2.2 Absolute Scattering Cross Sections.- 4.2.3 Relative Scattering Coefficients.- 4.3 Ratio of the Raman Scattering Cross Section in the Liquid and in the Gaseous State.- 4.4 Conclusion.- References.- 5. Intermolecular Forces Revealed by Raman Scattering.- 5.1 Introductory Remarks.- 5.2 Spectral Function for Raman Scattering.- 5.3 Impact Theory.- 5.4 Isolated Lines.- 5.4.1 Calculation of Line Widths and Shifts.- a) Non-Perturbative Approaches.- b) Perturbative Approaches.- c) Line Shift.- 5.4.2 Comparison of Theory with Experiment and Information Obtained about Intermolecular Potentials.- 5.5 Overlapping Lines and Band Shapes.- 5.6 Statistical Theories.- 5.7 Liquids.- 5.8 Conclusion.- References.- 6. The Resonance Raman Effect.- 6.1 Resonance Raman Scattering.- 6.2 Diatomic Molecules.- 6.2.1 Discrete Resonance Raman Scattering.- 6.2.2 Continuum Resonance Raman Scattering.- 6.2.3 Perturbed Diatomic Molecules.- 6.3 Polyatomic Molecules.- 6.4 Porphyrin Compounds.- 6.4.1 Porphyrin Absorption Spectrum.- 6.4.2 Helpful Diagrams.- 6.4.3 Scattering from Q0, Q1, and B.- 6.4.4 Anomalous Polarization.- 6.4.5 Interference Effects.- 6.4.6 Non-Adiabatic Effects.- 6.4.7 Influence of Jahn-Teller Distortion.- 6.5 Concluding Remarks.- References.- 7. Coherent Anti-Stokes Raman Spectroscopy.- 7.1 Theory.- 7.1.1 Maxwell’s Equations for Macroscopic Samples.- 7.1.2 Symmetry Properties of ?(3)258.- 7.1.3 CARS Amplitudes.- 7.1.4 Raman Amplitudes.- 7.1.5 Microscopic Third-Order Susceptibilities.- 7.2 Comparison of CARS and Raman Spectroscopy.- 7.2.1 Signal Strengths.- 7.2.2 Lineshapes and Maxima.- 7.2.3 Selection Rules.- 7.2.4 Orientation Averaging and Polarization Behavior.- 7.3 Experimental Aspects of CARS.- 7.4 Survey of CARS Experimental Results.- 7.4.1 Solids.- 7.4.2 Liquids.- 7.4.3 Gases.- a) Combustion and Gas Diagnostics.- b) Plasma Diagnostics.- c) Photochemical, Kinetic and Excited State Studies.- d) High-Resolution Spectroscopy.- 7.4.4 Solutions.- 7.4.5 Background Suppression in CARS.- 7.5 Summary.- References.- Additional References with Titles.