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-fl
ight mass spectra and were converted to the absolute partial cross sec
tions for the production of SO2+, SO+, S+(O-2(+)), O+, and SO2+ by usi
ng 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 di
ssociation pathways of the SO2+ and SO22+ ions, some of which are firs
t observed in the present study. These pathways are discussed by compa
ring them with the reported electronic states of the ions. (C) 1998 Am
erican Institute of Physics.