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Title: Electron-impact ionization of B/sup 2+/ and O/sup 5+/: Excitation-autoionization in Li-like ions

Abstract

New measurements for the total, single ionization of B/sup 2+/ and O/sup 5+/ by electron impact are reported with particular attention directed to the indirect contribution of excitation-autoionization. For B/sup 2+/ these are the first measurements to our knowledge while for O/sup 5+/ the present data improve on previous measurements. In both cases the direct total ionization cross sections are in good agreement with recent distorted-wave predictions of Younger, and the excitation-autoionization contribution is consistent with measurements for other Li-like ions. For O/sup 5+/ an additional small increase in the cross section is observed at an energy well below the excitation-autoionization threshold; this feature may be attributable to resonance recombination followed by auto-double-ionization. For the Li-like ions Be/sup +/, B/sup 2+/, C/sup 3+/, N/sup 4+/, and O/sup 5+/, the ionization theory of Younger is used as a basis to subtract the direct ionization component from the total measured ionization cross sections in order to extract the 1s/sup 2/2s..-->..summation/sub l/1s2s2l excitation cross section. The deduced inner-electron excitation cross sections are quantitatively compared with excitation theory including new close-coupling calculations for Be/sup +/ and B/sup 2+/ presented here. For all cases except Be/sup +/, the close-coupling theory is in agreement with themore » deduced experimental excitation cross sections. These new results and analysis improve confidence in excitation theory for highly charged ions.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
OSTI Identifier:
5138472
Resource Type:
Journal Article
Journal Name:
Phys. Rev. A; (United States)
Additional Journal Information:
Journal Volume: 34:3
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; BORON IONS; ELECTRON-ION COLLISIONS; IONIZATION; OXYGEN IONS; AUTOIONIZATION; BEAM-BEAM INTERACTIONS; CORRECTIONS; ISOELECTRONIC ATOMS; MULTICHARGED IONS; TOTAL CROSS SECTIONS; ATOMS; BEAM DYNAMICS; CHARGED PARTICLES; COLLISIONS; CROSS SECTIONS; ELECTRON COLLISIONS; ION COLLISIONS; IONS; 640304* - Atomic, Molecular & Chemical Physics- Collision Phenomena

Citation Formats

Crandall, D H, Phaneuf, R A, Gregory, D C, Howald, A M, Mueller, D W, Morgan, T J, Dunn, G H, Griffin, D C, and Henry, R J.W. Electron-impact ionization of B/sup 2+/ and O/sup 5+/: Excitation-autoionization in Li-like ions. United States: N. p., 1986. Web. doi:10.1103/PhysRevA.34.1757.
Crandall, D H, Phaneuf, R A, Gregory, D C, Howald, A M, Mueller, D W, Morgan, T J, Dunn, G H, Griffin, D C, & Henry, R J.W. Electron-impact ionization of B/sup 2+/ and O/sup 5+/: Excitation-autoionization in Li-like ions. United States. https://doi.org/10.1103/PhysRevA.34.1757
Crandall, D H, Phaneuf, R A, Gregory, D C, Howald, A M, Mueller, D W, Morgan, T J, Dunn, G H, Griffin, D C, and Henry, R J.W. 1986. "Electron-impact ionization of B/sup 2+/ and O/sup 5+/: Excitation-autoionization in Li-like ions". United States. https://doi.org/10.1103/PhysRevA.34.1757.
@article{osti_5138472,
title = {Electron-impact ionization of B/sup 2+/ and O/sup 5+/: Excitation-autoionization in Li-like ions},
author = {Crandall, D H and Phaneuf, R A and Gregory, D C and Howald, A M and Mueller, D W and Morgan, T J and Dunn, G H and Griffin, D C and Henry, R J.W.},
abstractNote = {New measurements for the total, single ionization of B/sup 2+/ and O/sup 5+/ by electron impact are reported with particular attention directed to the indirect contribution of excitation-autoionization. For B/sup 2+/ these are the first measurements to our knowledge while for O/sup 5+/ the present data improve on previous measurements. In both cases the direct total ionization cross sections are in good agreement with recent distorted-wave predictions of Younger, and the excitation-autoionization contribution is consistent with measurements for other Li-like ions. For O/sup 5+/ an additional small increase in the cross section is observed at an energy well below the excitation-autoionization threshold; this feature may be attributable to resonance recombination followed by auto-double-ionization. For the Li-like ions Be/sup +/, B/sup 2+/, C/sup 3+/, N/sup 4+/, and O/sup 5+/, the ionization theory of Younger is used as a basis to subtract the direct ionization component from the total measured ionization cross sections in order to extract the 1s/sup 2/2s..-->..summation/sub l/1s2s2l excitation cross section. The deduced inner-electron excitation cross sections are quantitatively compared with excitation theory including new close-coupling calculations for Be/sup +/ and B/sup 2+/ presented here. For all cases except Be/sup +/, the close-coupling theory is in agreement with the deduced experimental excitation cross sections. These new results and analysis improve confidence in excitation theory for highly charged ions.},
doi = {10.1103/PhysRevA.34.1757},
url = {https://www.osti.gov/biblio/5138472}, journal = {Phys. Rev. A; (United States)},
number = ,
volume = 34:3,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 1986},
month = {Mon Sep 01 00:00:00 EDT 1986}
}