Electron-impact excitation of ions in the magnesium sequence: Fe XV

Journal Article · Mon Jul 01 04:00:00 EDT 1985 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.32.93· OSTI ID:5475494

Christensen, R B; Norcross, D W; Pradhan, A K

Intermediate-coupling collision strengths are calculated for all transitions between the states 3s/sup 2/ /sup 1/S/sub 0/, 3s3p( /sup 3/P/sub 0,1,2/, /sup 1/P/sub 1/), 3p/sup 2/( /sup 1/D/sub 2/, /sup 3/P/sub 0,1,2/, /sup 1/S/sub 0/), 3s3d( /sup 3/D/sub 1,2,3/, /sup 1/D/sub 2/), and 3s4s( /sup 3/S/sub 1/, /sup 1/S/sub 0/). Calculations are carried out in a ten-state distorted-wave approximation. Resonance effects are considered by using multichannel quantum-defect theory, and relativistic effects in the target Hamiltonian are taken into account in the Breit-Pauli formulation. The important 3s/sup 2/ /sup 1/S/sub 0/--3s3p /sup 3/P/sub 1/ transition is found to be subject to large resonance enhancement, as previously shown by other workers for less highly charged Mg-like ions. Term coupling among the target states also affects several transitions considerably. Present results are compared with previous calculations; some significant differences are noted. The new results suggest a serious discrepancy between calculated and observed relative intensities of the 284.2-A (resonance) and 417.3-A (intercombination) lines for Fe XV in the Sun, but will reduce the discrepancy for this ratio for other Mg-like ions observed in tokamak plasmas.

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards, Boulder, Colorado 80309
• OSTI ID: 5475494
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 32:1; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALINE EARTH METALS
ASTROPHYSICS
ATOMS
CHARGED PARTICLES
CLOSED PLASMA DEVICES
COLLISIONS
COUPLING
CROSS SECTIONS
DISTORTED WAVE THEORY
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
ELEMENTS
ENERGY-LEVEL TRANSITIONS
EXCITATION
INTERMEDIATE COUPLING
ION COLLISIONS
IONS
IRON IONS
ISOELECTRONIC ATOMS
MAGNESIUM
METALS
MULTICHARGED IONS
RESONANCE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES