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Title: Electron-impact ionization of P-like ions forming Si-like ions

We have calculated electron-impact ionization (EII) for P-like systems from P to Zn{sup 15+} forming Si-like ions. The work was performed using the flexible atomic code (FAC) which is based on a distorted-wave approximation. All 3ℓ → nℓ' (n = 3-35) excitation-autoionization (EA) channels near the 3p direct ionization threshold and 2ℓ → nℓ' (n = 3-10) EA channels at the higher energies are included. Close attention has been paid to the detailed branching ratios. Our calculated total EII cross sections are compared both with previous FAC calculations, which omitted many of these EA channels, and with the available experimental results. Moreover, for Fe{sup 11+}, we find that part of the remaining discrepancies between our calculations and recent measurements can be accounted for by the inclusion of the resonant excitation double autoionization process. Lastly, at the temperatures where each ion is predicted to peak in abundances in collisional ionization equilibrium, the Maxwellian rate coefficients derived from our calculations differ by 50%-7% from the previous FAC rate coefficients, with the difference decreasing with increasing charge.
Authors:
 [1] ;  [2]
  1. Nuclear Data Center, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)
  2. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
Publication Date:
OSTI Identifier:
22351530
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 784; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; AUTOIONIZATION; COMPARATIVE EVALUATIONS; CROSS SECTIONS; DISTORTED WAVE THEORY; EQUILIBRIUM; EXCITATION; INCLUSIONS; IONS