A study of the unimolecular dissociation of SO+2(Ctilde;,Dtilde;,Etilde;) using the photoelectronndash;photoion coincidence method

摘要

Photoelectronndash;photoion coincidence spectra for SO+2, SO+, and S+resulting from the photoionization of SO2over the photon energy range of 15.5ndash;17.2 eV (720ndash;800 Aring;) have been obtained at an electron energy resolution of ape;40 meV (full width at half maximum). The breakdown diagram is presented for SO+2, SO+, and S+. For excited SO+2(Ctilde;,Dtilde;,Etilde;) ions formed initially with internal energies in the range of 4.18ndash;4.87 eV, the breakdown curves for the three ions are relatively smooth. The relative yields for the formation of S+, SO+, and SO+2via radiative stabilization are approximately 1:80:20. The lack of structure observed in the breakdown curves in this internal energy region is consistent with the conclusion that rapid internal conversion occurs prior to ionic decay. For the SO+2internal energy range of 3.88ndash;4.18 eV, the S+breakdown curve is structured, suggesting that the formation of S+follows a statehyphen;specific dissociation pathway. The results of the present experiment do not support the previous findings that the SO+2and S+product channels are only formed for photon energies le;16.7 eV.