A five-dimensional quantum dynamics study of the F(2P) + CH4 reaction.

By applying the semirigid vibrating rotor target (SVRT) model to the title reaction, five-dimensional wave packet quantum dynamics calculations have been carried out on the new potential energy surface PES-2006 [Espinosa-Garcia et al., J. Phys. Chem. A 111, 2761 (2007)]. The reaction probabilities have been calculated for total angular momentum J up to 105 to obtain the converged integral cross sections over a collision energy range of 0.01-0.345 eV. With the polyatomic system initially in its ground rovibrational state |000>, no obvious resonance signature has been observed in the integral cross sections although it appears in the reaction probabilities for J < or = 40. However, when the umbrella mode of the collision system is initially excited to nu(alpha0) = 1 level, |001> state, there is resonance signature in both the reaction probabilities with J < or = 55 and the integral cross sections. In addition, rate constants are calculated by Boltzmann averaging of the |000> integral cross sections over collision energy and compared with both the previous kinetic calculations and the experimental measurements. A reasonable agreement has been achieved over the investigated temperature range of 180-400 K.