EFFECTIVE COLLISION STRENGTHS FOR ELECTRON-IMPACT EXCITATION OF Fe VIII

Journal Article · Tue Dec 20 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/743/2/206· OSTI ID:22004395

Tayal, S S ^[1]; Zatsarinny, O ^[2]

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1. Department of Physics, Clark Atlanta University, Atlanta, GA 30314 (United States)
2. Department of Physics and Astronomy, Drake University, Des Moines, IA 50311 (United States)

New extensive calculations are reported for electron collision strengths, rate coefficients, and transition probabilities for the astrophysically important lines of Fe VIII. The collision strengths have been calculated in the close-coupling approximation using the B-spline Breit-Pauli R-matrix method. The multiconfiguration Hartree-Fock method with term-dependent non-orthogonal orbitals is employed for an accurate representation of the target wave functions. The close-coupling expansion includes 102 fine-structure levels of Fe VIII covering all possible terms of the ground 3p {sup 6}3d and singly excited 3p {sup 5}3d{sup 2}, 3p {sup 6}4l, 3p {sup 5}3d4s, 3s3p {sup 6}3d{sup 2}, and 3p {sup 6}5l configurations. The present calculations are more extensive than the previous ones, leading to a total 5151 transitions between fine-structure levels. The effective collision strengths are obtained by averaging the electron collision strengths over a Maxwellian distribution of velocities and these are tabulated for all fine-structure transitions at electron temperatures in the range from 5 Multiplication-Sign 10{sup 3} to 5 Multiplication-Sign 10{sup 6} K. There is an overall good agreement with the previous 77-state calculations by Griffin, Pindzola, and Badnell, but significant differences are also noted for some transitions.

• OSTI ID: 22004395
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 743; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
ELECTRON COLLISIONS
ELECTRON TEMPERATURE
EXCITATION
HARTREE-FOCK METHOD
IRON
R MATRIX
WAVE FUNCTIONS