Experimental and computational studies of the kinetics of the reaction of hydrogen atoms with carbon disulfide

Abstract Pulsed laser photolysis at 193 nm of NH 3 /CS 2 mixtures in an Ar bath gas combined with resonance fluorescence detection of atomic H yielded the rate constant for H + CS 2 over 295–490 K. The reaction was found to be pressure dependent and in the fall-off region or near the low pressure limit. Fitting to the Troe formalism yielded k 0  = 7.5 × 10 −24 ( T /300 K) −14.76 exp(−5180 K/ T ) cm 6  molecule −2  s −1 over 295–490 K. At 490 K equilibration of adduct formation was observed which yielded a H-SCS bond dissociation enthalpy of 73 ± 10 kJ mol −1 . These observations are consistent with W1 results for the potential energy surface and comparison suggests HSCS is the major addition product. Transition state theory yields an estimate for the high-pressure limit of addition over 290–300 K of 1.3 × 10 −9 exp(−7.2 kJ mol − 1 /RT) cm 3  molecule −1  s −1 . Uncertainties are discussed in the text.