Theoretical Models for Atomic Charge Transfer in Ion-Atom Collisions

Abstract

The current theoretical models for the description of electron transfer in adiabatic, intermediate and high-energy collisions are reviewed. Particular emphasis is laid on the recent development of atomic theories suited for fast or asymmetric ion-atom encounters. The comparison with other theories and with experimental data on total as well as differential capture cross sections is used to determine the applicability of a specific model. The selected examples concern capture to bound states, to continuum states, radiative transfer as well as capture in the presence of an isolated nuclear resonance.

Direct observation of swap cooling in atom-ion collisions

“…We now discuss the probability for resonant-chargeexchange in a collision. RCEx has been extensively studied theoretically [21][22][23] and has been experimentally investigated for collision energies ranging from eV to keV for different species, including Rubidium [24]. Here we use ) Fig.…”

Charge transfer from coherent elliptic states

“…Experiments with Rydberg atoms offer an excellent area for working out such a plan. CT from inner atomic shells, in particular the K shell, has already given important generic insights relevant to states of low angular momentum (see, for instance, [2] or [3]), but with Rydberg states it is possible to study the capture dynamics in much more detail by systematically varying the initial conditions.…”

Investigation of electron capture in swift C4+ (1s2s 3S) collisions with gas targets using a zero-degree Auger projectile spectroscopy apparatus built with the L45 beam line at the ‘Demokritos’ 5.5MV tandem accelerator

“…Ion-atom collisions are typically divided into three not-so-distinct velocity regimes, characterized by the projectile velocity V p compared to the classical orbiting velocity v e of the active electron in its initial or final state. The three regimes are defined as the adiabatic or slow (V p v e ) regime, the intermediate (V p ≈ v e ) regime and the high-energy or fast (V p v e ) [63] regime. As a point of reference, the electron velocities of He (or H 2 ) are 3.73 mm/ns (3.35 mm/ns for H 2 ), 0.073 MeV/u (or 0.058 MeV/u) and 1.70 au (or 1.53 au) [64], while the projectile velocities of this thesis are in the range of 9.82-15.52 mm/ns (0.5-1.25 MeV/u or 4.49-7.09 au).…”