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Proceedings Paper

Laser Pyrolysis Techniques: Application To Catalysis, Combustion Diagnostics, And Kinetics
Author(s): Gregory P Smith
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Paper Abstract

A pulsed laser pyrolysis method has been developed to study kinetic processes at high temperatures. A CO2 laser is used to irradiate a 100 torr mixture of an infrared absorber (SF6), bath gas (N2), and reactants. Rapid heating to 700-1400 K occurs, followed by two-stage cooling. Unimolecular reactions are studied by competitive kinetics with a known standard, using mass-spectrometric or gas-chromatographic analysis. Bimolecular processes are examined using laser-induced fluorescence (LIF). The technique offers great advantages in reaching reactive temperatures in a fast and time-resolved manner, without the complications of hot surfaces. It is thus an ideal tool for analyzing and measuring some of the basic processes occurring in more complicated, real, hot systems. Our recent applications of the laser pyrolysis method in the areas of catalysis and combustion are summarized here. Several transition metal-carbonyl bond dissociation energies have been measured, and catalysis by the hot metal particulate products was observed. Since the use of LIF as a flame diagnotic requires some knowledge of the fluorescence quenching rates at high temperatures, the laser pyrolysis method was used to measure these rates for the important OH radical. Its reaction rate with acetylene was also measured, with implications for flame modeling and the mechanism of soot formation. Finally, this method can be used to ignite low concentrations of fuel and oxidant, and then study the time-resolved evolution of the flame chemistry by LIF and chemiluminescence observations.

Paper Details

Date Published: 31 May 1984
PDF: 6 pages
Proc. SPIE 0458, Applications of Lasers to Industrial Chemistry, (31 May 1984); doi: 10.1117/12.939405
Show Author Affiliations
Gregory P Smith, SRI International (United States)


Published in SPIE Proceedings Vol. 0458:
Applications of Lasers to Industrial Chemistry
Richard L. Woodin; Andrew Kaldor, Editor(s)

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