Fast reactions of polar molecules in processes with no activation energy

The rate constants of ion-molecule and radical recombination reactions involving polar species have been calculated using an intermolecular potential averaged over the molecular orientations. A transition state is proposed in which the two species are confined in a square potential well. The energy of the system within the well is then quantized. Calculations using the square potential well model show that electrostatic effects cannot be ignored for these polar species, and they give good agreement with experimental rate determinations.