Dissociation dynamics in the dissociative electron attachment to carbon dioxide

Abstract

Dissociative electron attachment (DEA) to gas phase ${\mathrm{CO}}_{2}$ has been probed using a velocity slice imaging technique. DEA to ${\mathrm{CO}}_{2}$ produces only an ${\mathrm{O}}^{\ensuremath{-}}$ ionic fragment and shows two major resonances located at 4.4 and 8.2 eV, respectively. The kinetic energy and angular distribution of the ${\mathrm{O}}^{\ensuremath{-}}$ ions are measured around the second resonance with higher efficiency and sensitivity that provide details of the DEA dynamics. The kinetic energy distributions are in good agreement with the previous reports. However, the distinct angular distributions show substantial difference from the two recent studies within the limited electron energies. Our angular distribution results show two negative ion resonant states are involved in the underlying DEA process at the entire electron energies over the second resonance. We discussed the recent conflicting findings in the angular distribution results. The forward-backward asymmetry observed in the angular distributions is explained due to the interference effect of different partial waves associated with the attaching electron.