Chemical accelerator studies of isotope effects on collision dynamics of ion–molecule reactions: Kr++HD

Abstract

The reaction of Kr+ with HD has been studied as a function of relative collision energy over the range 0.08–3.1 eV (c.m.) by measuring integral reaction cross sections and the velocity vector distributions of product ions formed when a collimated, energy selected beam of Kr+ impinges on HD under single collision conditions. The ratio σ (KrH+)/σ (KrD+) passes through a sharp maximum (?2.5) at about 0.7 eV relative collision energy and decreases by a factor of 10 at higher energies. The isotopic product velocity vector distributions show a high but not perfect degree of symmetry about the center of mass at low energies but are extremely anisotropic at high energies, with the KrH+ being strongly forward scattered and the KrD+ being back scattered.