Abstract
A single centered expansion with a finite Hilbert basis set has been used to calculate the electron removal probabilities for He+ and He by antiproton and proton projectiles. Single and double ionization cross sections of He are calculated under the independent event and the independent particle model from 10 keV to 1 MeV for antiprotons and 25 keV to 1 MeV for protons. Results for p-+ He+ are in good agreement with recent calculations based on a numerical solution to the time-dependent Schrodinger equation but experimental measurements are unavailable. For He single ionization, cross sections calculated via the independent event and independent particle models for antiproton projectiles are in good agreement with experiment above 40 keV but differ below this value. Double ionization results for p-+ He are in excellent agreement with experiment from 10 keV to 300 keV but fall below experiment above 300 keV. Results of p+ + He single ionization cross sections are in excellent agreement with experiment for both models above 50 keV, with the independent event model being slightly preferred below this value. And in contrast to antiprotons, double ionization cross sections for protons are in poor agreement with experiment.
Wehrman, Laurence Allan (1997). Single and double ionization of helium within the independent event model. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1997 -THESIS -W34.