Three-Body Coulomb Problem Probed by Mapping the Bethe Surface in Ionizing Ion-Atom Collisions

Abstract

The three-body Coulomb problem has been explored in kinematically complete experiments on single ionization of helium by 100 MeV/u C(6+) and 3.6 MeV/u Au(53+) impact. Low-energy electron emission ( E(e)<150 eV) as a function of the projectile deflection theta(p) (momentum transfer), i.e., the Bethe surface [15], has been mapped with Delta theta(p)+/-25 nanoradian resolution at extremely large perturbations ( 3.6 MeV/u Au(53+)) where single ionization occurs at impact parameters of typically 10 times the He K-shell radius. The experimental data are not in agreement with state-of-the-art continuum distorted wave-eikonal initial state theory.

Projectile coherence effects in electron capture by protons colliding with H2and He

“…For the same collision system for which measured differential electron spectra are nicely reproduced by theory (3.6 MeV/amu Au 53+ + He, η = 4.5 [3]) severe discrepancies are observed in the double differential cross sections (DDCS) as a function of electron energy and projectile momentum transfer q [4]. In fully differential cross sections (FDCS) significant discrepancies were even observed for very small η (0.1) [5], for which the collision dynamics was thought to be essentially understood.…”

Recoil-ion and electron momentum spectroscopy: reaction-microscopes

“…Recently, multiply or even fully differential cross sections have been reported for strong perturbations as well Moshammer et al 2001;Fischer et al 2003a) yielding dramatic disagreement with essentially all non-perturbative theoretical models at hand. Similar as for small perturbations, the proper treatment of the full three-body dynamics seems to represent a major challenge for theory (see also Olson and Fiol 2001).…”

Evidence for significant projectile–target nucleus scattering in single ionization of helium

“…The projectile -electron interaction is manifested in double differential cross sections as a function of the electron energy and the transverse component of the momentum transfer q ⊥ . There, a ridge of enhanced intensity (known as the Bethe ridge) extending along a line for which p e = q ⊥ is observed [19], where p e is the electron momentum. In order to study the role of the projectile -target nucleus interaction in more detail, we analyzed the equivalent cross sections, i.e.…”