Direct MP2 molecular dynamics studies of H atom reaction with CD _4 and CH_4

摘要

The mechanism and dynamics of the H + CD_4 → CD_3 + HD (I) and H + CH_4 → CH_3 + H_2 (II) reactions have been investigated by electronic structure methods. The minimum-energy path and vibrational frequencies along the intrinsic reaction coordinate are calculated at MP2/cc-pVDZ level. Energy distributions of the products are also obtained by the direct classical trajectory calculations at the MP2/ cc-pVDZ level. It is found that most of the available energy appears as product translational energy, and very little of the available energy is partitioned into internal excitation of the HD (H_2) product for reaction I (II), which is in agreement with the experimental evidence. The results indicate that the experimental results could be reproduced by the direct MP2 molecular dynamics calculations. The rotational state distributions of the products show the HD (H_2) products are formed with lower rotational quantum numbers than the CD_3 (CH_3) products.