QUANTUM DYNAMICAL STUDY OF HEAVY-LIGHT-HEAVY REACTIONS: APPLICATION TO THE (Cl + CH4 в†’ HCl + CH3) REACTION
A. H. Moussa1, M. Shalaby1, H. Talaat1, S.El-Wallid Sedik2, M.T. El-Din Kamal2
1Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt
2Theoretical Physics Department, National Research Center, Dokki, Giza, Egypt
esedik@gmail.com
Keywords: reaction dynamics, potential surface, normal modes, Cl + CH в†’ HCl + CH reaction
Abstract
A time dependent quantum-mechanical QM study is performed on the Cl + CH4 → HCl + CH3 reaction, using a pseudotriatomic ab initio based surface. Probabilities present some clear peaks versus t, which we assign to transition state resonances where the light H atom oscillates between heavy Cl and CH3 groups. For ground-state reactants, the reactivity is of quantum origin. The reaction occurs through an abstraction mechanism, following both direct and an indirect mechanisms. The calculations show the participation of a short-lived collision complex in the microscopic reaction mechanism. This theoretical result and other oscillating properties found here could, however, be related to the existence of resonance for the production of HCl, as suggested by experimentalists.
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