Electron impact excitation collision strengths for extreme ultraviolet lines of Fe VII

Journal Article · Tue Jun 10 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/788/1/24· OSTI ID:22356695

Tayal, S. S. ^[1]

---

1. Department of Physics, Clark Atlanta University, Atlanta, GA 30314 (United States)

Extensive calculations have been performed for electron impact excitation collision strengths and oscillator strengths for the Fe VII extreme ultraviolet lines of astrophysical importance. The collision strengths for fine-structure transitions are calculated in the B-spline Breit-Pauli R-matrix approach. The target wavefunctions have been calculated in the multiconfiguration Hartree-Fock method with term-dependent non-orthogonal orbitals. The close-coupling expansion includes 189 fine-structure levels of Fe VII belonging to terms of the ground 3p {sup 6}3d {sup 2} and excited 3p {sup 5}3d {sup 3}, 3p {sup 6}3d4l, 3p {sup 6}3d5s, and 3p {sup 6}3d5p configurations. The effective collision strengths are determined from the electron excitation collision strengths by integration over a Maxwellian distribution of electron velocities. The effective collision strengths are provided for 17766 fine-structure transitions at electron temperatures from 10{sup 4} to 10{sup 7} K. Our results normally agree with the previous R-matrix frame-transformation calculations by Witthoeft and Badnell. However, there are important differences for some transitions with the previous calculations. The corrections to the previous results are mainly due to more extensive expansions for the Fe VII target states.

• OSTI ID: 22356695
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 788; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
COLLISIONS
CONFIGURATION
COUPLING
DISTRIBUTION
ELECTRON TEMPERATURE
ENERGY LEVELS
EXCITATION
EXPANSION
EXTREME ULTRAVIOLET RADIATION
FINE STRUCTURE
HARTREE-FOCK METHOD
IRON
OSCILLATOR STRENGTHS
R MATRIX
TRANSFORMATIONS
VELOCITY
WAVE FUNCTIONS