Dissociation dynamics of transient anion formed via electron attachment to sulfur dioxide

We report the molecular dynamics of dissociative electron attachment to sulfur dioxide (⁠$SO2$⁠) by measuring the momentum distribution of fragment anions using the velocity slice imaging technique in the electron energy range of 2–10 eV. The $S−$ channel results from symmetric dissociation which exhibits competition between the stretch mode and bending mode of vibration in the excited parent anion. The asymmetric dissociation of parent anions leads to the production of $O−$ and $SO−$ channels where the corresponding neutral fragments are formed in their ground as well as excited electronic states. We also identify that internal excitation of $SO−$ is responsible for its low yield at higher electron energies.