Electron processes in ion-atom collisions with emphasis on elliptic Rydberg target atoms.

摘要

Close-coupling calculations for electron capture in {dollar}rm Csp6{dollar}+H(1s) collisions have been carried out at intermediate velocities. A propensity rule for the population of the magnetic substates of the projectile is displayed, when choosing the quantization axis to be perpendicular to the scattering plane. The propensity rule states that {dollar}m = -l{dollar} is predominantly populated. It is demonstrated that the propensity rule makes it possible to reduce the basis set in the close-coupling calculations by only including the {dollar}m = -l{dollar} substate for each l. Such a reduction is most useful in close-coupling calculations for collisions with highly charged ions.; Electron capture from excited Na(4dm) atoms by K{dollar}sp+{dollar} ions is studied for laboratory energies around 1 keV by means of close-coupling calculations. The dependence of the electron capture cross section on the magnetic quantum number of the initial state is interpreted in terms of the localization of the initial electron distribution on the target in the vicinity of the collision plane. Comparison with existing experimental data is done.; The rather new field of electron capture from elliptic Rydberg target is studied by performing close-coupling calculations for H{dollar}sp+{dollar} colliding with elliptic H(n =3,4,5). The electron capture cross section has been calculated for different (a) projectile speed and directions and (b) eccentricities of the target. The calculated capture cross sections show a strong dependence on the projectile direction and on the eccentricity, which may be understood in terms of velocity matching. This dependence is very similar to what is seen in experiments on collisions between Na{dollar}sp+{dollar} and elliptic Li(n = 25) at the same relative collision velocity. Thus, the dependence of the capture cross section on projectile direction and target eccentricity is not very sensitive to the principal quantum number of the elliptic target. For elliptic H(n = 4) target ionization is studied as well.