Keywords and Phrases
Few-body problem; Fully-differential study; Higher-order contributions; Ionization of H2 and He; Post-collision Interaction; Velocity-matching
”Advancing our understanding of the few-body dynamics in simple atomic systems is one of the most important goals of atomic scattering research. In perturbation theory, this goal entails accurately describing the relative contributions from first versus higher-order mechanisms. One higher-order mechanism that is particularly important for target ionization by a charged-particle impact is known as post-collision interaction (PCI). There, the projectile and the ejected electron interact with each other at least twice. In the first interaction, the projectile transfers sufficient energy for the electron to be lifted to the continuum. The second interaction occurs in the outgoing part of the collision, where the projectile and the electron attract each other towards the initial beam axis. It is well known that PCI maximizes when the electrons are ejected with a speed close to that of the projectiles. However, a systematic study on a fully differential level of ionization by ion impact was lacking for this kinematic regime. Kinematically complete experiments on ionization of H2 and He by 75 keV proton impact were performed. Fully differential cross sections (FDCS) were extracted for a broad range of fixed electron energies for each of the targets. Pronounced post-collisional effects between the projectile and the ejected electrons were observed. The results were compared with two conceptually similar calculations, both based on distorted wave approaches. Surprising discrepancies were observed between the experimental data and theory, and also between conceptually similar theoretical models. This shows that the FDCS are very sensitive to the details of the underlying few-body dynamics in this region. Data also indicated the limitations of perturbative methods and the need for non-perturbative approaches”--Abstract, page iv.
Schulz, Michael, 1959-
Madison, Don H.
Parris, Paul Ernest, 1954-
Madria, Sanjay Kumar
Ph. D. in Physics
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Few-body dynamics underlying postcollision effects in the ionization of H2 by 75-keV proton impact
- Target dependence of postcollision interaction effects on fully differential ionization cross sections
- Ejected-electron-energy and angular dependence of fully differential ionization cross sections in medium-velocity proton collisions with He and H2
ix, 114 pages
© 2020 Madhav Dhital, All rights reserved.
Dissertation - Open Access
Dhital, Madhav, "Fully differential study of higher-order contributions to the few-body dynamics of simple atomic systems" (2020). Doctoral Dissertations. 2949.