Non-adiabatic transitions in the reaction of fluorine with methane
1Theoretische Chemie, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
Abstract:
Reactions of methane with different atoms are benchmark examples of elementary reaction processes intensively studied by theory and experiment. Due to the presence of conical intersections and spin-orbit coupling, non-adiabatic transitions can occur in reactions with F, Cl, or O atoms. Extending detailed quantum theory beyond the Born-Oppenheimer approximation for polyatomic reaction processes, non-adiabatic wave packet dynamics calculations studying the F(2P3/2)/F*(2P1/2) + CHD3 → HF + CD3 reaction on accurate vibronically and spin-orbit coupled diabatic potential energy surfaces are presented. Non-adiabatic transitions are found to increase the reactivity compared to Born-Oppenheimer theory and are more prominent than in triatomic reactions previously studied. Furthermore, the lifetimes of reactive resonances are reduced. The reactivity of F(2P3/2) is found to exceed the one of F*(2P1/2) even at low collision energies.
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