Scattering of Ions

In the elastic differential cross-section of the N+-rare gas systems two different types of oscillations have been observed. At an energy of a few eV a primary rainbow was detected for all systems. In the case of N+ —Ar, secondary rainbows were resolved too. From these experimental data the potential depths were determined to be : e (N+ — Ne) = 0.4 eV, s (N + — Kr) = 0.29 eV, f ( N + — Xe) = 0.92 eV. For the system N+ —Ar the shape of the reduced potential was obtained by evaluating the positions of the secondary rainbow extrema. The potential depth was found to be 2.16 eV. At higher energies and large scattering angles additional oscillations appeared which are presumed to be Stueckelberg oscillations. For N+ —Ne a single group of strongly marked oscillations appeared up to the highest energies used (EL = 220 eV) . In the case of N+ —Ar the amplitudes of these undulations are strongly quenched. For N+ —Kr and N+ —Xe several groups of oscillations with different amplitudes and frequencies seem to be superimposed in the differential cross-section. They are attributed for all systems to crossings of the incoming state with the charge exchanged state.