Quasiclassical trajectory study of the effect of antisymmetric stretch mode excitation on the O(³P) + CH₄(ν₃ = 1) → OH + CH₃ reaction on an analytical potential energy surface. Comparison with experiment

Motivated by a recent crossed-beam experiment on the title reaction reported by Pan and Liu [J. Chem. Phys. 140, 191101 (2014)], a detailed dynamics study was performed at three collision energies using quasiclassical trajectory (QCT) calculations based on a full-dimensional potential energy surface recently developed by our group (PES-2014). Although theory/experiment agreement is not yet quantitative, in general the theoretical results reproduce the experimental evidence: the vibrational branching ratio of OH(v = 1)/OH(v = 0) is ∼0.8/0.2, excitation of the antisymmetric CH stretching mode in methane increases reactivity by factor 2.28–1.50, although an equivalent amount as translational energy is more efficient in promoting the reaction and, finally, product angular distribution shifts from backward in the CH₄(ν = 0) ground-state to sideways when the antisymmetric CH stretching mode is excited. These results give confidence to the PES-2014 surface, depend on the quantization procedure used, are comparable with recent QCT calculations or improve previous theoretical studies using a different surface, and demonstrate the utility of the theory/experiment collaboration