Translational energy dependence and potential energy surfaces of gas phaseS(N)2 and addition-elimination reactions

The translational energy dependence of several gas-phase S(N)2 and carbonyl addition-elimination reaction rate constants has been measured in an FT-IC R. The relative energy dependences of the reactions are qualitatively consi stent with variations in the reaction potential surfaces that are inferred from their thermal rate constants, which comprise a wide range of reaction efficiencies. Furthermore, the observed energy dependence of each reaction agrees quantitatively with RRKM calculations of the reaction rate constants . We conclude that, although nonstatistical dynamics are observed in some S N2 reactions, statistical reaction rate theory is, in general, an accurate means of interpreting the translational energy dependence of bimolecular io n-molecule reaction rate constants.