Formula omitted] velocity images of dissociative electron attachment to OCS

Abstract

Dissociative electron attachments to OCS with the attachment energies of 4.3, 4.7, 5.0, 6.2, 6.5, 6.8, and 7.0eV are investigated by measuring the S− momentum distributions with time-sliced anion velocity image mapping technique. In this energy range, the ground-state fragmentation, e−+OCS→CO(X˜1Σ+)+S−(2Pu), is only one dissociation pathway allowed in energy. All velocity images show the predominant feature of the low-speed S− ions, but the middle- and high-speed S− ions appear at the higher attachment energies (6.2–7.0eV). The trimodel speed distribution of S− ion should be attributed to the different populations of the rovibrational states of CO fragment, however, the dynamic details of above dissociations are still unclear and demand theoretical calculations.