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dc.contributorVirginia Tech
dc.contributor.authorBautista, M. A.
dc.contributor.authorQuinet, P.
dc.contributor.authorPalmeri, P.
dc.contributor.authorBadnell, N. R.
dc.contributor.authorDunn, J.
dc.contributor.authorArav, N.
dc.date.accessioned2014-05-14T17:03:34Z
dc.date.available2014-05-14T17:03:34Z
dc.date.issued2009-12
dc.identifier.citationBautista, M. A. et al., "Radiative transition rates and collision strengths for Si II," A&A 508, 1527-1537 (2009) DOI: 10.1051/0004-6361/200913179
dc.identifier.issn0004-6361
dc.identifier.urihttp://hdl.handle.net/10919/48022
dc.description.abstractAims. This work reports on radiative transition rates and electron impact excitation collision strengths for levels of the 3s(2)3p, 3s3p(2), 3s(2)4s, and 3s(2)3d configurations of Si II. Methods. The radiative data were computed using the Thomas-Fermi-Dirac-Amaldi central potential, but with the modifications introduced by Bautista (2008) that account for the effects of electron-electron interactions. We also introduce new schemes for the optimization of the variational parameters of the potential. Additional calculations were carried out with the Relativistic Hartree-Fock and the multiconfiguration Dirac-Fock methods. Collision strengths in LS-coupling were calculated in the close coupling approximation with the R-matrix method. Then, fine structure collision strengths were obtained by means of the intermediate-coupling frame transformation (ICFT) method which accounts for spin-orbit coupling effects. Results. We present extensive comparisons between the results of different approximations and with the most recent calculations and experiments available in the literature. From these comparisons we derive a recommended set of g f-values and radiative transition rates with their corresponding estimated uncertainties. We also study the effects of different approximations in the representation of the target ion on the electron-impact collision strengths. Our most accurate set of collision strengths were integrated over a Maxwellian distribution of electron energies and the resulting effective collision strengths are given for a wide range of temperatures. Our results present significant differences from recent calculations with the B-spline non-orthogonal R-matrix method. We discuss the sources of the differences.
dc.description.sponsorshipNASA Astronomy and Physics Research and Analysis Program (Award NNX09AB99G)
dc.description.sponsorshipSpace Telescope Science Institute (project GO-11745)
dc.description.sponsorshipBelgian F.R.S.-FNRS
dc.language.isoen_US
dc.publisherEDP SCIENCES
dc.subjectatomic data
dc.subjectatomic processes
dc.subjectline: formation
dc.subjectquasars: absorption
dc.subjectlines
dc.subjectsun: abundances
dc.subjectism: atoms
dc.subjectk-vacancy states
dc.subjectauger decay data
dc.subjectr-matrix method
dc.subjectoscillator-strengths
dc.subjectelectron-scattering
dc.subjectatomic structures
dc.subjectgeneral
dc.subjectprogram
dc.subjectlines
dc.subjections
dc.subjectlifetimes
dc.subjectastronomy & astrophysics
dc.titleRadiative transition rates and collision strengths for Si II
dc.typeArticle
dc.identifier.urlhttp://www.aanda.org/articles/aa/pdf/2009/48/aa13179-09.pdf
dc.date.accessed2014-05-08
dc.title.serialAstronomy & Astrophysics
dc.identifier.doihttps://doi.org/10.1051/0004-6361/200913179


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