Laser-Induced Chemical Processes

ISBN-13: 9781468438659 / Angielski / Miękka / 2012 / 288 str.

Jeffrey I. Steinfeld

Opis

The possibility of initiating chemical reactions by high-intensity laser exci tation has captured the imagination of chemists and physicists as well as of industrial scientists and the scientifically informed public in general ever since the laser first became available. Initially, great hopes were held that laser-induced chemistry would revolutionize synthetic chemistry, making possible "bond-specific" or "mode-specific" reactions that were impos sible to achieve under thermal equilibrium conditions. Indeed, some of the early work in this area, typically employing high-power continuous-wave sources, was interpreted in just this way. With further investigation, however, a more conservative picture has emerged, with the laser taking its place as one of a number of available methods for initiation of high-energy chemical transformations. Unlike a number of these methods, such as flash photolysis, shock tubes, and electron-beam radiolysis, the laser is capable of a high degree of spatial and molecular localization of deposited energy, which in turn is reflected in such applications as isotope enrichment or localized surface treatments. The use of lasers to initiate chemical processes has led to the discovery of several distinctly new molecular phenomena, foremost among which is that of multiple-photon excitation and dissociation of polyatomic molecules. This research area has received the greatest attention thus far and forms the focus of the present volume."

Spis treści

1. Vibrational Excitation in Polyatomic Molecules.- 1.1. Introduction.- 1.2. Complete Model.- 1.3. Application to SF6.- 1.4. Application to S2F10.- 1.5. Comparison with Another Complete Model.- 1.6. Comparison with a Thermal QC Model.- References.- 2. Multiphoton Infrared Excitation and Reaction of Organic Compounds.- 2.1. Introduction.- 2.2. Features Distinguishing Large from Small Molecules.- 2.3. Selected Literature Survey.- 2.3.1. Unimolecular Reactions.- 2.3.2. Bimolecular Organic Reactions.- 2.3.3. Sensitized Organic Reactions.- 2.3.4. Low-Intensity CW Infrared Multiphoton Dissociation.- 2.4. Application of Chemical Thermometers in Pulsed Infrared Laser Photochemistry.- 2.4.1. “Thermal” vs. “Nonthermal” Processes.- 2.4.2. Choice of Thermal Monitor Molecule.- 2.4.3. Complications in Utilizing Chemical Thermometers.- 2.4.4. Determining Effective Temperature and Reaction Time.- 2.5. Experimental Data for Ethyl Acetate.- 2.5.1. Dependence of Reaction Probability on Fluence.- 2.5.2. Dependence of Cross Section on Fluence.- 2.5.3. Energy Absorption.- 2.6. Computer Modeling Studies.- 2.6.1. Literature Models.- 2.6.2. Model Calculations with a Master Equation Formulation for Large Organic Molecules.- References.- 3. Sinterable Powders from Laser-Driven Reactions.- 3.1. Introduction.- 3.2. Laser-Heated Powder Synthesis.- 3.2.1. Process Description.- 3.2.2. Analyses and Characterizations.- 3.3. Summary.- References.- 4. Laser-Induced Chemical Reactions: Survey of the Literature, 1965–1979.- 4.1. Introduction.- Table 4.1A Reactions Directly Induced by Single- and MultipleInfrared-Photon Absorption.- Table 4.1B Thermal and Photosensitized Infrared Laser Induced Reactions.- Table 4.2 Reactions Induced by Visible and Ultraviolet Laser Excitation.- Table 4.3 Miscellaneous Laser-Induced Effects.- 4.2 References for Tables 4.1–4.3.- 4.3 Selected Review Articles, Monographs, and References to Theory and Diagnostic Techniques.- Author Index.