Kinematic study of O− -ion formation from dissociative electron attachment to SO2

Abstract

We report a complete kinematic study of ${\mathrm{O}}^{\ensuremath{-}}$-ion formation due to dissociative electron attachment to ${\mathrm{SO}}_{2}$ using the velocity slice imaging technique in the incident electron energy range over the resonances. Two resonances are observed at 5.2 and 7.5 eV, respectively. From the kinetic energy distribution, the two resonances are observed to have the same threshold energy, pointing to the fact that the two processes, giving rise to the two resonant peaks, have the same dissociation limit. From the angular distribution results we identified the involvement of an ${A}_{1}$ and a combination of ${A}_{1}+{B}_{2}$ temporary negative-ion state(s) for the first and second resonances, respectively.