Photoacoustic, Photothermal and Photochemical Processes in Gases

ISBN-13: 9783642838538 / Angielski / Miękka / 2011 / 252 str.

Peter Hess; R. T. Bailey; S. Bernegger

Opis

Gas-phase photoacoustics are treated comprehensively for the first time in this book. Review articles by leading scientists in the respective research areas introduce their fields, review present knowledge and conclude with the latest developments and future prospects. Topics covered include the theory of photoacoustics in the frequency and time domains, acoustic resonator models, a great variety of experimental setups and techniques, studies of spectrocopy and fundamental kinetic processes such as energy transfer and chemical reactions, and applications such as air and exhaust monitoring and trace gas detection in biology and agriculture. The book will interest newcomers to photoacoustics, since it gives an overview of the important directions of current research and detailed descriptions of experimental methods. It will also be a valuable source of information for those already involved in photoacoustic research due to its clear presentation of theory and experimental results. All relevant literature references in this rapidly expanding field of laser applications are included.

Spis treści

1. Principles of Photoacoustic and Photothermal Analysis.- 1.1 Photoinduced Processes and Detection.- 1.1.1 Variety of Processes.- 1.1.2 Detection Methods.- 1.1.3 Literature Review.- 1.2 Principles of Photoacoustics.- 1.2.1 Basic Considerations.- 1.2.2 Time and Frequency Domain Analysis.- 1.2.3 Resonant and Nonresonant Operation.- 1.2.4 Detection Devices.- 1.3 Recent Advances and Developments.- 1.3.1 Theory.- 1.3.2 Fundamental Constants and Thermophysical Properties.- 1.3.3 Kinetic Processes.- 1.3.4 Applications in Trace Analysis and Pollution Monitoring.- 1.4 Summary and Outlook.- References.- 2. Theoretical Foundation of Photoacoustics in the Frequency and Time Domains.- 2.1 The Equations of Linear Gas Dynamics.- 2.2 Theory of the Cylindrical Optoacoustic Resonator.- 2.3 The Pulse Source Thermal Lens Effect.- 2.4 Thermal Recovery.- 2.5 Short Time-Scale Measurements.- 2.6 Improved Models for the Pulsed Source Thermal Lens.- 2.7 Optics of the Thermal Lens.- 2.8 Conclusions.- References.- 3. Thermal Lensing.- 3.1 Introduction.- 3.1.1 Survey of Approaches.- 3.1.2 Configurations.- 3.2 Experimental.- 3.2.1 Laser Sources.- 3.2.2 Probe Lasers.- 3.2.3 Laser Beam Tailoring.- 3.2.4 Laser Beam Alignment Techniques.- 3.2.5 Beam Splitting and Combining.- 3.2.6 Sample Cells.- 3.2.7 Signal Detection.- 3.2.8 Signal Retrieval.- 3.3 Theory.- 3.3.1 The Pulsed Source Experiment.- 3.3.2 The Modulated Source Experiment.- 3.3.3 The Transverse and Collinear Photothermal Lens.- 3.4 Applications.- 3.4.1 Determination of Energy Transfer Rate Constants.- 3.4.2 Transport Phenomena.- 3.4.3 Photochemistry.- 3.4.4 Surface Phenomena.- 3.4.5 Spectroscopies.- 3.4.6 Photoacoustic Diagnostics.- 3.4.7 Laser Physics.- 3.5 Summary.- References.- 4. Spherical Acoustic Resonators.- 4.1 Introduction.- 4.2 Basic Theory.- 4.3 Steady-State Response.- 4.4 Wave Modes.- 4.5 Thermal and Viscous Boundary Layers.- 4.6 Precoundensation Effects.- 4.7 Bulk Dissipation and Relaxation.- 4.8 Shell Motion.- 4.9 Imperfect Spherical Geometry.- 4.10 Ducts and Slits in the Shell Wall.- 4.11 Measurement of the Speed of Sound.- 4.12 Thermophysical Information from the Speed of Sound.- References.- 5. Laser Excitation of Acoustic Modes in Cylindrical and Spherical Resonators: Theory and Applications.- 5.1 Introduction.- 5.1.1 History.- 5.1.2 Recent Developments.- 5.1.3 Scope of Review.- 5.2 Optical Excitation of Acoustic Modes.- 5.2.1 General Considerations.- 5.2.2 Acoustical Resonances in a Cylinder.- 5.2.3 Acoustical Resonances in a Sphere.- 5.2.4 Accuracy of the Resonance Method.- 5.3 Experimental Method.- 5.3.1 Apparatus.- 5.3.2 Temperature Measurement.- 5.3.3 Computer Control.- 5.4 Theory.- 5.4.1 General Remarks.- 5.4.2 Basic Equations.- 5.4.3 Kinetics in the Frequency Domain.- 5.4.4 Helmholtz Equations.- 5.4.5 Boundary Conditions.- 5.4.6 Solutions.- 5.5 Applications.- 5.5.1 Chemical Reaction.- 5.5.2 Energy Transfer.- 5.5.3 Thermophysical Properties and Fundamental Constants.- 5.5.4 Condensation Effects.- 5.5.5 Intracavity Experiments.- 5.6 Conclusions.- References.- 6. Application of the Photoacoustic Effect to Studies of Gas Phase Chemical Kinetics.- 6.1 Pulsed Excitation.- 6.1.1 Signal Description.- 6.1.2 Experimental Results.- 6.2 Continuous Excitation.- 6.2.1 Theory.- 6.2.2 Experimental Results.- 6.3 Nonlinear Effects.- 6.4 Chemical Amplification.- 6.5 Unimolecular Reactions.- 6.6 Direct Detection of Reactants and Products.- 6.7 Flames, Combustion, and Other Applications.- References.- 7. Atmospheric and Exhaust Air Monitoring by Laser Photoacoustic Spectroscopy.- 7.1 Introduction.- 7.1.1 Air Pollution.- 7.1.2 Methods for Monitoring Gaseous Pollutants.- 7.2 Basic Principles of Trace Gas Detection by Laser Photoacoustic Spectroscopy.- 7.2.1 Generation of Photoacoustic Signal.- 7.2.2 Main Characteristics.- 7.3 Experimental Arrangements for Laser Photoacoustic Spectroscopy.- 7.3.1 Tunable Lasers.- 7.3.2 Modulation Techniques.- 7.3.3 Cell Design.- 7.3.4 Detection Schemes.- 7.4 Previous PA Studies on Trace Gases.- 7.4.1 Measurements on Certified Gases.- 7.4.2 Measurements on Real Air Samples.- 7.5 Stationary CO-Laser PA System.- 7.5.1 Spectral Range.- 7.5.2 Experimental Arrangement.- 7.5.3 PA Measurements on Vehicle Exhausts.- 7.6 Mobile CO2-Laser PA System.- 7.6.1 Spectral Range.- 7.6.2 Experimental Arrangement.- 7.6.3 Trace Gas Measurements.- 7.7 Conclusion.- References.- 8. Trace Detection in Agriculture and Biology.- 8.1 Photoacoustic Detection of Ethylene Production in Plants.- 8.1.1 The Choice of Ethylene.- 8.1.2 Experimental Setup.- 8.1.3 Ethylene Production During Senescence of Carnation and Orchid Flowers.- 8.1.4 Growth of Docks (Rumex Species) Under Flooded Conditions.- 8.2 Comparison of Chlorophyll Fluorescence and Photoacoustic Transients in Spinach Leaves.- 8.2.1 Photosynthetic Energy Conversion, Chlorophyll Fluorescence and Photoacoustic Transients in Spinach Leaves.- 8.2.2 Experimental Setup.- 8.2.3 Results and Discussion.- 8.3 Potentialities of Photoacoustic Sensing.- 8.3.1 Potential Use of Photoacoustic Sensing in Greenhouses, Stables, Fumigation Chambers, Storage Compartments and in Meteorological Studies.- 8.3.2 Leaf Chamber for Adsorption Studies.- 8.3.3 Olfactory Psychophysics.- 8.3.4 Aerobic Meat Spoilage.- 8.3.5 Heat Pipe Cell.- 8.3.6 Soilless Growth.- 8.4 Conclusion.- References.