An ab initio molecular dynamics study of the roaming mechanism of the H2 + HOC+ reaction

We report here a direct ab initio molecular dynamics study of the p-/o-H-2 + HOC+ reaction on the basis of the accurate SAC-MP2 potential energy surface. The quasi-classical trajectory method was employed. This work largely focuses on the study of reaction mechanisms. A roaming mechanism was identified for this molecular ion-molecule reaction. The driving forces behind the roaming mechanism were thoroughly investigated by using a trajectory dynamics approach. In addition, the thermal rate coefficients of the H-2 + HOC+ reaction were calculated in the temperature range [25, 300] K and are in good agreement with experiments.