In keeping with a 1992 gas-phase study (J. Am; Chem. Sec. 1992, 114, 7146), MP2(FULL)/6-31 + G(d) ab initio calculations find no potential energy minimum for the elusive (CH3)(2)S.-OH intermediate of the tropospheric reaction of dimethylsulfide (DMS) with hydroxyl radical. A dipole-dipole complex, (CH3)(2)S...HO., is found to be stabilized against dissociation to DMS and OH. by Delta(r,298) = 17 kJ mol(-1) but destabilized by Delta S-r,S-298 = 68 J mol(-1) K-1. The reaction of DMS with OH. is predicted to prefer formation of CH3SCH2. and H2O, which is 105 kJ mol(-1) exothermic and requires only 4 kJ mol(-1) activation energy. The heat of formation and adiabatic and vertical ionization energies of methanesulfenic acid are calculated at the G2(MP2) level of theory as Delta H-f,H-298 = -141.8 kJ mol(-1), IE(a) = 8.71 eV, and IE(v) = 9.17 eV. The O-H and C-H bond dissociation energies (BDE) in CH3SOH differ with BDE(O-H) = 287.4 kJ mol(-1) being lower than BDE(C-H) = 397 kJ mol(-1). The heats of formation and ionization energies of CH3SO. and .CH2SOH are calculated at Delta H-f,H-298(CH3SO.) = -77.4 kJ mol(-1), Delta H-f,H-298(.CH2SOH) = 32.2 kJ mol(-1), IE(a) (.CH3SO.) = 8.57 eV, and IE(a)(.CH2SOH) = 6.80 eV. The .CH2SH=0 isomer is calculated to be 205 kJ mol(-1) less stable than CH3SO..