Observation of the dynamics leading to a conical intersection in dissociative electron attachment to water

Abstract

Following prior work on the lower-energy resonances, we apply techniques of momentum imaging and ab initio scattering calculations to the process of dissociative electron attachment to water via the highest-energy ${}^{2}{B}_{2}$ resonance. We focus on the H${}^{\ensuremath{-}}$ anion fragment, which is produced via dynamics passing through and avoiding the conical intersection with the lower ${A}_{1}$ state, leading to OH (${}^{2}\ensuremath{\Pi}$) and OH (${}^{2}\ensuremath{\Sigma}$), respectively. The momentum imaging technique, when combined with theoretical calculations on the attachment amplitude and dissociation dynamics, demonstrates that the angular distributions provide a signature of the location of the conical intersection in the space of nuclear configurations.