Application of semirigid vibrating rotor target model to the reaction of O(3P)+CH4 → CH3+OH

In this paper, the SVRT (semirigid vibrating rotor target) model has been applied to study the reaction of O(P-3) + CH4 --> CH3 + OH using the time-dependent wave packet (TDWP) method. Employing the basic SVRT model, quantum dynamics calculation for any atom-polyatom reaction involves only four mathematical dimensions (4D). The reaction probability, cross section, and rate constant from the initial ground state are calculated for the title reaction on potential energy surfaces of Corchado et al. (C-T) and Jordon and Gilbert (JG). The calculated reaction probabilities on the C-T surface are significantly smaller than those calculated on the JG surface. The difference in barrier height is insufficient to account for the difference in the magnitude of reaction probabilities on two surfaces. Instead, global contour plots show that the C-T surface appears to have incorrect contour lines near the reaction region which tend to help reflect the wave packet back toward the entrance channel. On the other hand, our calculated rate constants on the JG surface are in good agreement with experimental measurements over a range of temperatures.