Searching for resonances in the reaction CL + CH4 -> HCL + CH3: Quantum versus cuasiclassical dynamics and comparison with experiments
- Martínez, R. 3
- González, M. 12
- Defazio, P. 4
- Petrongolo, C. 45
- 1 Centre de Recerca en Quimica Teorica, Parc Cientific de Barcelona, C/Marti i Franqùs 1, 08028 Barcelona, Spain
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2
Universitat de Barcelona
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3
Universidad de La Rioja
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4
Università degli Studi di Siena
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- 5 Istituto per i Processi Chimico-Fisici Del CNR, Dipartimento di Chimica, Via Giuseppe Moruzzi 1, 56100 Pisa, Italy
ISSN: 0021-9606
Année de publication: 2007
Volumen: 127
Número: 10
Pages: 1-8
Type: Article
D'autres publications dans: Journal of Chemical Physics
Projets liés
Résumé
A quantum-mechanical (QM) and quasiclassical trajectory (QCT) study was performed on the title reaction, using a pseudotriatomic ab initio based surface. Probabilities and integral cross sections present some clear peaks versus the collision energy Ecol, which we assign to Feshbach resonances of the transition state, where the light H atom oscillates between the heavy Cl and C H3 groups. For ground-state reactants, reactivity is essentially of quantum origin (QCT observables and oscillations are smaller, or much smaller, than QM ones), and the calculated integral cross section and product distributions are in reasonable agreement with the experiment. The reaction occurs through an abstraction mechanism, following both a direct and an indirect mechanism. The quasiclassical trajectory calculations show the participation of a short-lived collision complex in the microscopic reaction mechanism. Finally, QCT differential cross sections of Cl+C H4 →HCl (′ =0 and 1) +C H3 oscillate versus Ecol, whereas experimentally this only occurs for HCl (′ =1). This theoretical result and other oscillating properties found here could, however, be related to the existence of a Feshbach resonance for the production of HCl (′ =1), as suggested by experimentalists. © 2007 American Institute of Physics.