Coincidence Measurements of Krypton-Krypton Collisions

In collisions of Kr⁺ ions with Kr atoms at keV energies, both particles from the same encounter are recorded in coincidence. The charge states m of the scattered particle and n of the recoil particle are measured, and the relative probability of such an ($m, n$) event is determined, together with the inelastic energy loss associated with that event. These data are analyzed using the statistically model of Everhart and Kessel. This model, which assumes m and n to be statistically independent of each other, fits the data fairly well. Ionization potentials for Kr⁺⁵ through Kr⁺⁹ are estimated from the data curves as interpreted by the statistical model. There is an active region in the Kr⁺ -Kr data at 25-keV incident energy and 9^∘{} scattering where the inelastic energy changes suddenly, and other anomalous effects are found. This is compared and contrasted with active regions previously found in Ne⁺ -Ne and Ar⁺ -Ar data.