Contributions of excitation autoionization to electron-impact ionization of Mg-like Al/sup +/, S/sup 4 +/, Cl/sup 5 +/, and Ar/sup 6 +/ ions

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

DOI:https://doi.org/10.1103/PhysRevA.33.3825· OSTI ID:5732234

Tayal, S S; Henry, R J.W.

The R-matrix method is used to calculate the contributions of excitation autoionization to electron-impact ionization in Mg-like Al/sup +/, S/sup 4 +/, Cl/sup 5 +/, and Ar/sup 6 +/ ions. The ground 3s/sup 2/ /sup 1/S state together with the autoionizing states arising from the 2p/sup 5/3s/sup 2/3p, 2p/sup 5/3s/sup 2/3d, 2p/sup 5/3s/sup 2/4s, 2s2p/sup 6/3s/sup 2/3p, 2s2p/sup 6/3s/sup 2/3d, and 2s2p/sup 6/3s/sup 2/4s configurations are included in the R-matrix expansion. Large numbers of bound terms of appropriate symmetry are included in the expansion to account for the resonant-excitation--double-autoionization process. The total ionization cross sections are obtained by combining the cross sections for inner-shell excitation with direct-ionization cross sections. Our calculation shows an abrupt and significant rise in the cross sections, in agreement with recent crossed-beam measurements of Howald et al. The importance of indirect processes over the direct process increases with increasing ionic charge along the sequence.

• Research Organization: Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001
• OSTI ID: 5732234
• Journal Information: Phys. Rev. A; (United States), Vol. 33:6
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ALUMINIUM IONS
ELECTRON-ION COLLISIONS
ARGON IONS
CHLORINE IONS
IONIZATION
SULFUR IONS
AUTOIONIZATION
EXCITATION
ISOELECTRONIC ATOMS
MULTICHARGED IONS
R MATRIX
TOTAL CROSS SECTIONS
ATOMS
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
ELECTRON COLLISIONS
ENERGY-LEVEL TRANSITIONS
ION COLLISIONS
IONS
MATRICES
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena