Study of S- and SO- ion formation from dissociative electron attachment to SO2

A detailed experimental investigation of the dissociative electron attachment (DEA) process to sulfur dioxide molecules in the gas phase has been performed. The sulfur dioxide molecule is known to produce O-, S- and SO- ions, mainly forming two prominent resonant peaks at around 4.2 and 7.5 eV incident electron energies. The S- and SO- ions are studied over the second resonance around 7.5 eV incident electron energy in detail using the well-established velocity slice imaging (VSI) spectrometer. The time-sliced images, kinetic energy and angular distribution have been reported for the two ions over the second resonance for the first time. Both the ions are seen to be formed with very low kinetic energies with their respective neutral fragments being produced in internally excited states. The angular distribution data also signifies the presence of a linear combination of A(1) and B-2 temporary negative ion states responsible for the resonant peak at 7.5 eV incident electron energy.