Angular Distributions for Near-threshold (e,2e) Processes for H, He, and Other Rare-gas Targets

Authors

• Cheng Pan, University of Nebraska-LincolnFollow
• Anthony F. Starace, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

4-1-1992

Citation

Published by American Physical Society

Physical Review A (1992) 45: 4588

http://pra.aps.org

Comments

Copyright © 1992, American Physical Society. Used by permission

Abstract

Distorted-wave calculations of the triply differential cross sections for electron-impact ionization of H, He, Ne, Ar, Kr, and Xe are presented for final-state electrons sharing ≤4 eV excess energy and for the coplanar, θ₁₂=π geometry. Results for H and He targets, presented briefly elsewhere [C. Pan and A. F. Starace, Phys. Rev. Lett. 67, 185 (1991)], are analyzed in greater detail and compared with available experimental and other theoretical results. In particular, for He targets the effects of exchange and of second-order capture processes are exhibited. These are shown to be of lesser importance than other short-range effects on the s-wave phase shifts of both incident and final-state continuum electrons for reproducing the experimentally observed target dependence of the electron angular distributions for H and He targets [P. Schlemmer, T. Rösel, K. Jung, and H. Ehrhardt, Phys. Rev. Lett. 63, 252 (1989)]. More approximate theoretical (e,2e) results for Ne, Ar, Kr, and Xe targets also show striking target dependences; they are compared with available experimental results.