Exploring the stereodynamics and microscopic mechanism of the O(3P) + CH4, CD4 → OH + CH3, OD + CD3 combustion reactions

•QCT dynamics study of low reactive conditions of a large experimental interest.•Rovibrational and two- and three-vector angular distributions are analysed.•Large changes occur in the stereodynamics depending on the OD vibrational level.•Results are interpreted in terms of two direct microscopic reaction mechanisms.

The dynamics of the O(3P) + CH4(X1A1) → OH(X2∏) + CH3(X2A″2) reaction and its isotopic variant with CD4 was studied at several collision energies (Ecol) of experimental interest, using the quasiclassical trajectory (QCT) method on the ground potential energy surface (GHMS PES). This ab initio analytical PES, previously developed using the OX(CX3) pseudo-triatomic approximation, allowed us to perform an exhaustive dynamics study of these low reactive systems. Around 300 million of trajectories were calculated to simulate the conditions of the low and intermediate Ecol experiments. The results describe in detail scalar and vector properties and the reactive microscopic mechanism, obtaining a generally good agreement with the experiments.

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