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Science 6 July 2007:
Vol. 317. no. 5834, pp. 102 - 105
DOI: 10.1126/science.1142373
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Reports

Understanding Reactivity at Very Low Temperatures: The Reactions of Oxygen Atoms with Alkenes

Hassan Sabbah,1 Ludovic Biennier,1 Ian R. Sims,1* Yuri Georgievskii,2 Stephen J. Klippenstein,3* Ian W. M. Smith4*

A remarkable number of reactions between neutral free radicals and neutral molecules have been shown to remain rapid down to temperatures as low as 20 kelvin. The rate coefficients generally increase as the temperature is lowered. We examined the reasons for this temperature dependence through a combined experimental and theoretical study of the reactions of O(3P) atoms with a range of alkenes. The factors that control the rate coefficients were shown to be rather subtle, but excellent agreement was obtained between the experimental results and microcanonical transition state theory calculations based on ab initio representations of the potential energy surfaces describing the interaction between the reactants.

1 Institut de Physique de Rennes, Laboratoire PALMS, UMR 6627 du CNRS–Université de Rennes 1, Equipe Astrochimie Expérimentale, Bat. 11c, Campus de Beaulieu, 35042 Rennes Cedex, France.
2 Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA.
3 Chemistry Division, Argonne National Laboratory, Argonne, IL 60439, USA.
4 University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.

* To whom correspondence should be addressed. E-mail: ian.sims{at}univ-rennes1.fr (I.R.S.); sjk{at}anl.gov (S.J.K.); i.w.m.smith{at}bham.ac.uk (I.W.M.S.)

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Chemical Dynamics Special Feature: Theoretical studies on bimolecular reaction dynamics.
D. C. Clary (2008)
PNAS 105, 12649-12653
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