UNIMOLECULAR DYNAMICS IN BIMOLECULAR ION-MOLECULE REACTIONS

We have measured the translational energy dependence of a series of ch loride exchange reactions in the gas phase. The translational energy d ependence varies with the changes in the potential energy surfaces acr oss the series of reactions in a manner that is consistent with the pr edictions of statistical reaction rate theory. These results indicate that despite reports of non-statistical behavior in simple S(N)2 react ions, the assumptions of unimolecular reaction rate theory (strong cou pling, energy randomization) are valid for the complexes formed in man y bimolecular ion-molecule collisions.