Reactions in Propylene and 1,3-Butadiene

One of the first studies of ion-molecule reactions employing photoionization was that of Koyano et These workers did not employ 

Rate constants measured for the reactions in 1,3-butadiene are given in Table I and compared with those measured by Barber et for reactant ions produced by electron impact. It is seen that the agreement between the two sets of rate constants is only fair, even if a correction factor is applied so that both quantities are made equal for one reaction. If the discrepancy is outside experimental error, it may have a very interesting origin. It should be remembered that the internal-energy distribution of the reactant ions produced by photoionization extends only to 10.19 eV - /, whereas the internal-energy distribution of ions produced by electron impact can extend up to the dissociation limit of the reactant 

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