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

Journal Article · Mon Sep 01 00:00:00 EDT 1986 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.34.1757· OSTI ID:5138472

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.

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.

• Research Organization: Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• OSTI ID: 5138472
• Journal Information: Phys. Rev. A; (United States), Vol. 34:3
• Country of Publication: United States
• Language: English

Related Subjects

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