Dissociative photoionization of SO2 from 16 to 120 eV

Using synchrotron radiation as a continuum light source, dissociative photoionization of SO2 has been studied in the photon-energy region of 16–120 eV. Ion branching ratios were obtained by analyzing time-of-flight mass spectra and were converted to the absolute partial cross sections for the production of SO2+, SO+, S+(O2+), O+, and SO2+ by using the reported total absorption cross sections of SO2. Ion branching ratios were differentiated with respect to the incident photon energy. The results obtained by this analytical photoion spectroscopy show dissociation pathways of the SO2+ and SO22+ ions, some of which are first observed in the present study. These pathways are discussed by comparing them with the reported electronic states of the ions.