Computational investigation of the peroxy radicals CH3S(O)nOO and the peroxynitrates CH3S(O)nOONO2 (n = 0, 1, 2)

► Computational study of CH3S(O)nOO, CH3S(O)nOONO2, (n = 0,1,2) and isomers. ► Calculated stability order of peroxy radicals: CH3S(O)2OO > CH3SOO > CH3S(O)OO. ► Similar order found for ΔE of CH3S(O)nOONO2 relative to CH3S(O)nOO + NO2. ► Results consistent with assignment of experimental IR frequencies to CH3S(O)2OONO2.