In this paper, we will report on fully differential cross sections (FDCS) for single ionization of helium by 75 keV proton impact for fixed ejected electron energies and different momentum transfers. These measurements show major discrepancies in the absolute magnitude between experiment and the theoretical, 3DW (three-distorted-wave) model. The 3DW model treats the collision as a three-body process (projectile, ion, ejected electron), and for the scattering plane it has accurately predicted the FDCS for higher energy C6+ impact ionization of helium. The lack of agreement between the 3DW model and experiment for low energy collisions suggests that a three-body model may not be appropriate for lower collision energies. We will present a four-body model that includes full initial-state correlation.
M. Foster et al., "Initial-State Correlation Effects in Low-Energy Proton Impact Ionization," Proceedings of the 13th International Symposium on Polarization and Correlation in Electronic and Atomic Collisions, American Institute of Physics (AIP), Jan 2006.
The definitive version is available at http://dx.doi.org/10.1063/1.2165612
13th International Symposium on Polarization and Correlation in Electronic and Atomic Collisions
Keywords and Phrases
Atom-Ion Collisions; Helium Neutral Atoms; Impact Ionisation; Numerical analysis
Article - Conference proceedings
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