Energy requirements for a chemical reaction. I. Halide ion transfer to antimony pentafluoride

Abstract

Using crossed seeded nozzle beams we have examined the energy dependence of the cross section for the reaction SbF5+RX→SbF5X−+R+, where X is a halogen and R an organic radical. By using a range of carrier gases in the two beams and by varying the nozzle temperature and the beam intersection angle, we can separately vary the relative translational energy and the vibrational temperatures of the beams. Near the threshold, vibrational energy seems to play a very important role. At energies well above threshold, the reactive cross section appears to depend largely on translational energy. We explain this by assuming that the reaction takes place on two potential energy surfaces. By choosing RX properly, the R+ product will decompose. In two cases we observe that, although vibrational energy in RX has a minor effect on the halide abstraction, it is very important in the subsequent decomposition of R+.