| Abstract
| - In this work, we present a complete study of the photoionization and dissociation processes for bis(trifluoromethoxy)disulfurylperoxide, CF3OS(O)2OOS(O)2OCF3, which was generated by UV photolysis ofa mixture of (CF3CO)2O, SO2, and O2 at a low temperature. The reaction product was detected and characterizedby the photoelectron (PE) and photoionization mass spectroscopy (PIMS). For comparison, the geometricand electronic structures of CF3S(O)2OS(O)2CF3 (a), CF3OS(O)2OS(O)2OCF3 (b), and CF3OS(O)2OOS(O)2OCF3 (c) were investigated by the combination of experiments and theoretical studies. The PES resultsshow that the outer electrons residing in nO(S=O) of b and c are more tightly bound than those of a. It isworthwhile mentioning that drastic changes occur in the geometry of c after one-electron ionization. Theneutral molecule exhibits a gauche structure with the SOOS dihedral angle of 124.4°. The first ionizationprocess happens on the O−O antibonding orbital. The remarkable geometric changes between the ground-state molecule and cation are computed to be the gauche-to-trans rotation of δSOOS and the prolongation ofthe S1−O1 single bond length. According to the calculated bond dissociation energies, the dissociation processwas discussed. The calculated results indicate that once the parent ion is formed, the dissociation of theS1−O1 bond to form CF3OSO2+ is inevitable.
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