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Full-Text Articles in Physical Sciences and Mathematics
Spin- And Fine-Structure-Resolved Ionization Of Krypton, S. Bellm, J. Lower, R. P. Mceachran, E. Weigold, Ciarán Ryan-Anderson, Don H. Madison
Spin- And Fine-Structure-Resolved Ionization Of Krypton, S. Bellm, J. Lower, R. P. Mceachran, E. Weigold, Ciarán Ryan-Anderson, Don H. Madison
Physics Faculty Research & Creative Works
The influence of exchange, correlation, and relativistic effects in the ionization of heavy-target atoms can be sensitively probed by kinematically complete studies involving spin-polarized electrons, in particular when the fine structure of the residual ion is resolved. We present spin asymmetries, triple differential cross sections, and branching ratios for the ionization, by 127.5-eV and 114.3-eV electrons, of ground-state krypton atoms leading to the Kr+ 4s 2S1/2, 4p5 2P1/2, and 4p5 2P3/2 states. In order to untangle contributions from different physical effects, the experimental results are compared to those from distorted-wave Born approximation calculations (non- and semirelativistic) in which bound-state and …
Absolute Cross Sections For The Ionization-Excitation Of Helium By Electron Impact, S. Bellm, J. Lower, E. Weigold, I. Bray, D. V. Fursa, K. Bartschat, Don H. Madison, Allison L. Harris
Absolute Cross Sections For The Ionization-Excitation Of Helium By Electron Impact, S. Bellm, J. Lower, E. Weigold, I. Bray, D. V. Fursa, K. Bartschat, Don H. Madison, Allison L. Harris
Physics Faculty Research & Creative Works
In a recent publication we presented detailed experimental and theoretical results for the electron-impact-induced ionization of ground-state helium atoms. The purpose of that work was to refine theoretical approaches and provide further insight into the Coulomb four-body problem. Cross section ratios were presented for transitions leading to excited states, relative to those leading to the ground state, of the helium ion. We now build on that study by presenting individual relative triple-differential ionization cross sections (TDCSs) for an additional body of experimental data measured at lower values of scattered-electron energies. This has been facilitated through the development of new electron-gun …
Investigating Many-Electron Exchange Effects In Electron-Heavy-Atom Scattering, S. Bellm, J. Lower, Z. Stegen, Don H. Madison, H. P. Saha
Investigating Many-Electron Exchange Effects In Electron-Heavy-Atom Scattering, S. Bellm, J. Lower, Z. Stegen, Don H. Madison, H. P. Saha
Physics Faculty Research & Creative Works
In a recent publication we presented measurements and distorted-wave Born approximation (DWBA) calculations for spin asymmetries resulting from the scattering of 148 eV spin-polarized electrons from ground-state xenon atoms. While achieving reasonably good agreement between theory and experiment by accounting for many-body exchange effects through a local exchange potential, sizable discrepancies remained in some cases. It was proposed that a more sophisticated treatment of exchange might be the key to obtaining better agreement. Here we present high-precision experimental results at a lower projectile-electron energy of 112 eV. Due to improvements made to our spectrometer, these data are of significantly-improved statistical …