THEORETICAL-STUDIES OF THE RSOO, ROSO, RSO2 AND HOOS (R=H, CH3) RADICALS

The geometries of the radicals HSOO, HOSO, HSO2 and HOOS have been opt imized at the MP2 = FULL/6-31G level, and energies obtained with Gaus sian-2 theory. Internal rotations and vibrational frequencies are anal yzed. The results yield values of DELTAH(f,298) for the four doublet r adicals of 111.5, -241.4, -141.4 and 58.9 kJ mol-1, respectively. Impl ications for reactions of interest in combustion and atmospheric chemi stry are discussed. The results are employed to derive DELTAH(f,0) for CH3SOO, CH3OSO and CH3SO2 of 91.8, -222.6 and -199.4 kJ mol-1, respec tively. The calculated CH3S-OO bond strength is in excellent accord wi th a recent measurement.