Investigation of dissociative electron attachment to water using ion momentum imaging

Abstract

The dynamics of the dissociative electron attachment (DEA) process to water (H₂O) and heavy water (D₂O) are investigated using the newly developed Velocity Map Imaging for low energy electron collisions. Where as the kinetic energy and angular distribution of the negative ion from water at the 6.5 eV resonance is found to be in excellent agreement with previous results, entirely different angular distributions are obtained at the two resonances at higher energies. We identify the 8.5 eV resonance as due to a ²B₁ state in contrast to what has been believed till now based on experimental and theoretical studies. Large anisotropy in the angular distribution of H⁻ and O⁻ ions is observed at the third resonance indicating interesting dynamics involved.