Abstract

We investigate ionization of atomic hydrogen by electron-and positron-impact. We apply the Coulomb-Born (CB1) approximation, various modified CB1 approximations, the three-body distorted wave (3DW) approximation, and the time-dependent close-coupling (TDCC) method to electron-impact ionization of hydrogen. For electron-impact ionization of hydrogen for an incident energy of approximately 76.45 eV, we obtain a deep minimum in the CB1 triply differential cross section (TDCS). However, the TDCC for 74.45 eV and the 3DW for 74.46 eV gave a dip in the TDCS. For positron-hydrogen ionization (breakup) we apply the CB1 approximation and a modified CB1 approximation. We obtain a deep minimum in the TDCS and a zero in the CB1 transition matrix element for an incident energy of 100 eV with a gun angle of 56.13ffi. Corresponding to a zero in the CB1 transition matrix element, there is a vortex in the velocity field associated with this element. For both electron-and positron-impact ionization of hydrogen the velocity field rotates in the same direction, which is anticlockwise. All calculations are performed for a doubly symmetric geometry; the electron-impact ionization is in-plane, and the positron-impact ionization is out-of-plane.

Department(s)

Physics

Publication Status

Open Access

Comments

National Science Foundation, Grant 1707792

Keywords and Phrases

Electron-impact ionization; Hydrogen; Positron-impact ionization; Velocity field; Vortices

International Standard Serial Number (ISSN)

2218-2004

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2024 The Authors, All rights reserved.

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Publication Date

01 Jun 2020

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