Translational energies from ionic fragmentation

Abstract

Statistical theories of unimolecular reactions are applied to determine the translational energies of fragments of ionic decomposition. The results are found to be in conflict with experimental measurements of translational energies of ions formed by electron or photon impact. However, a full application of phase-space theory results in much better agreement with ion–molecule experiments than the theory of Safron et al. [S. A. Safron, N. D. Weinstein, D. R. Herschbach, and J. C. Tully, Chem. Phys. Lett. 12, 564 (1972)]. A classical model of a triatomic molecule is constructed, and the partitioning of energy in dissociating trajectories is examined and compared to statistical theories. Discrepancies between the trajectories and statistical theories are noted and possible explanations discussed.