Laser initiated chain reactions: A generalized extension to complex chemical chain systems

Article abstract of DOI:10.1063/1.441883

We present a generalized extension of the detailed kinetic and experimental analysis for studying rapid gas phase chemical chain reactions initiated by short pulse laser photolysis.The key ingredients of the technique are pulsed laser initiation of the chain by dissociation of a small fraction of a precursor molecule to produce radicals (Cl2 <*> Cl + Cl), followed by time resolved, infrared chemiluminescence detection of product HCl(v) emission from the propagation steps (Cl radical + RH <*> R radical + HC(v), R + Cl2 <*> Cl radical <*> + RCl). This laser initiated chain reaction technique is now extended to encompass a far wider range of chain kinetic rates, mechanisms, and product state distributions.Three prototypical systems are investigated which demonstrate distinctly different facets of the extended technique: (1) Cl2/HBr - a slow chain reaction system, (2) Cl2/CH3SH - a multiple chain reaction system, and (3) Cl2/H2 - a slow starting chain reaction system in which the product emission appears after an intital induction period.Quantitative rate data are obtained for several chain propagation steps: Br radical + Cl2 -> Cl radical + BrCl, k = 2.4(+/-0.2)x10^-15 cm³ molecule ^-1 s^-1; Cl radical + CH3SH -> radical CH2SH + HCl(v), k = 4.3(+/-1)x10^-12 cm³ molecule^-1 s^-1; radical CH2SH + Cl2 -> Cl radical + ClCH2SH, k = 2.6(+/-1)x10^-13 cm³ molecule ^-1 s^-1. The results illuminate a more general approach to precise kinetic and mechanistic studies of complex chain reactions under nearly ideal psuedo-first-order laboratory conditions.

Full text of DOI:10.1063/1.441883

Laser initiated chain reactions: A generalized extension to complex chemical chain
systems
David J. Nesbitt and Stephen R. Leone
Citation: The Journal of Chemical Physics 75, 4949 (1981); doi: 10.1063/1.441883
View online: http://dx.doi.org/10.1063/1.441883
View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/75/10?ver=pdfcov
Published by the AIP Publishing
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
On: Mon, 22 Dec 2014 22:37:23

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
On: Mon, 22 Dec 2014 22:37:23

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 132.248.9.8
On: Mon, 22 Dec 2014 22:37:23