First principles quantum dynamics study reveals subtle resonance in polyatomic reaction: The case of F + CH4 → HF + CH3

First principles quantum dynamics calculation has been carried out to investigate a recently observed resonance feature in the F + CH4 reaction by molecular beam experiment [W.C. Shiu, J.J. Lin, K.P. Liu, Phys. Rev. Lett., 92 (2004) 103201]. The generalized semi-rigid vibrating rotor target (GSVRT) method is employed to perform the quantum dynamics calculation on new ab initio potential energy surfaces (PES) constructed from the extensive high level ab initio calculations. A resonance near the reaction threshold energy is observed in both the calculated microscopic reaction probabilities and integral cross-sections on the ZYH2 PES. The calculated resonance on the ZYH2 PES is in good agreement with the experimental observation. This resonance feature is highly quantum mechanical and sensitive to the accuracy of ab initio energies.