We have measured and calculated fully differential cross sections for target ionization in 16-MeV O7++He and 24-MeV O8++Li collisions. As in previous studies, in the case of the He target we observe a pronounced forward shift in the angular distribution of the electrons relative to the direction of the momentum transfer q at small q (q < 1 a.u.). An unexpected result is that we also find a strong forward shift at large q (q > 2 a.u.), while at intermediate q this shift becomes very weak or even turns into a backward shift. For the Li target, in contrast, the forward shift monotonically increases with increasing q. These observations are qualitatively reproduced by our calculations. The comparison to theory suggests that at large q the forward shift is due to the postcollision interaction between the outgoing projectile and the ejected electron, but at small q it is mostly due to an interplay between the projectile-target core interaction and the electron-target core interaction.
M. Schulz and B. Najjari and A. B. Voitkiv and K. R. Schneider and X. Wang and A. C. Laforge and R. Hubele and J. Goullon and N. Ferreira and A. H. Kelkar and M. Grieser and R. Moshammer and J. H. Ullrich and D. Fischer, "Postcollision Effects in Target Ionization by Ion Impact at Large Momentum Transfer," Physical Review A - Atomic, Molecular, and Optical Physics, vol. 88, no. 2, pp. 022704-1 - 022704-7, American Physical Society (APS), Aug 2013.
The definitive version is available at https://doi.org/10.1103/PhysRevA.88.022704
Keywords and Phrases
Core Interactions; Ejected Electrons; Fully Differential Cross Sections; Ion Impact; Large Momentum Transfers; Li Targets; Post Collision Interaction; Post-collision; Ion Bombardment; Ionization; Lithium; Projectiles
International Standard Serial Number (ISSN)
Article - Journal
© 2013 American Physical Society (APS), All rights reserved.
01 Aug 2013