We use quasiclassical trajectories to study the reaction C(3P) + H2 → CH + H using an accurate ab initio potential surface, making comparisons with recent product distribution measurements. An analysis of the reactive trajectories indicates that the formation of CH + H is completely dominated by insertion to form a 3CH2 intermediate. However, this C insertion is initiated from nearly linear C-H-H geometries rather than by perpendicular attack as has been found for other insertion reactions (like O(1D) + H2). Perpendicular insertion collisions do occur, but they are almost always nonreactive due to poor coupling between modes initially excited in 3CH2 and the product reaction coordinate (C-H stretch). The calculated product rovibrational distributions are in excellent agreement with experiment, but we find that they are not sensitive to the presence of this modified insertion mechanism. Reactions like O(1D) + H2 may also show the modified insertion mechanism at high energies. Results from C + HD and C + HCl are also examined.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry