A quantum model Hamiltonian to treat reactions of the type X+YCZ(3)-> XY+CZ(3): Application to O(P-3)+CH4 -> OH+CH3

In this paper we present a model Hamiltonian to treat the dynamics of react ions of the general type X + YCZ(3)--> XY + CZ(3), where the CZ(3) group ha s C-3 upsilon symmetry. The main assumption of the model is that CZ(3) main tains its symmetry during the reaction. The Hamiltonian we derive can be us ed as the starting point for more simplified models. We present here one of these simpler models and use it to study the role of the umbrella vibratio nal motion in the reaction O(P-3) + CH4--> OH + CH3. Finally, we compare ou r results with previous theoretical and experimental results. (C) 2000 Amer ican Institute of Physics. [S0021-9606(00)00503-1].