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Science 25 November 1994:
Vol. 266. no. 5189, pp. 1359 - 1364
DOI: 10.1126/science.266.5189.1359
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Articles

The Validity of the "Diradical" Hypothesis: Direct Femtoscond Studies of the Transition-State Structures

S. Pedersen 1, J. L. Herek 1, and A. H. Zewail 1

1 Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA

Direct studies of diradicals, the molecular species hypothesized to be archetypal of chemical bond transformations in many classes of reactions, have been made using femtosecond laser techniques with mass spectrometry in a molecular beam. These studies are aimed at "freezing" the diradicals in time and in the course of the reaction. The passage of these species through the transition-state region was observed and the effect of total energy and alkyl substitution on the rates of bond closure and cleavage was examined. The results establish the nature of these intermediates and define their existence during reactions.

Submitted on August 26, 1994
Accepted on September 23, 1994


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Singlet Diradicals: from Transition States to Crystalline Compounds.
D. Scheschkewitz, H. Amii, H. Gornitzka, W. W. Schoeller, D. Bourissou, and G. Bertrand (2002)
Science 295, 1880-1881
   Abstract »    Full Text »    PDF »
Femtosecond Activation of Reactions and the Concept of Nonergodic Molecules.
E. W. Diau, J. L. Herek, Z. H. Kim, and A. H. Zewail (1998)
Science 279, 847-851
   Abstract »    Full Text »
Diradicals: Conceptual, Inferential, and Direct Methods for the Study of Chemical Reactions.
J. A. Berson (1994)
Science 266, 1338-1339
   PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)