Radiative transition rates and collision strengths for Si II

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dc.contributorVirginia Techen
dc.contributor.authorBautista, M. A.en
dc.contributor.authorQuinet, P.en
dc.contributor.authorPalmeri, P.en
dc.contributor.authorBadnell, N. R.en
dc.contributor.authorDunn, J.en
dc.contributor.authorArav, Nahumen
dc.contributor.departmentPhysicsen
dc.date.accessed2014-05-08en
dc.date.accessioned2014-05-14T17:03:34Zen
dc.date.available2014-05-14T17:03:34Zen
dc.date.issued2009-12en
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.en
dc.description.sponsorshipNASA Astronomy and Physics Research and Analysis Program (Award NNX09AB99G)en
dc.description.sponsorshipSpace Telescope Science Institute (project GO-11745)en
dc.description.sponsorshipBelgian F.R.S.-FNRSen
dc.identifier.citationBautista, M. A. et al., "Radiative transition rates and collision strengths for Si II," A&A 508, 1527-1537 (2009) DOI: 10.1051/0004-6361/200913179en
dc.identifier.doihttps://doi.org/10.1051/0004-6361/200913179en
dc.identifier.issn0004-6361en
dc.identifier.urihttp://hdl.handle.net/10919/48022en
dc.identifier.urlhttp://www.aanda.org/articles/aa/pdf/2009/48/aa13179-09.pdfen
dc.language.isoen_USen
dc.publisherEDP SCIENCESen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectatomic dataen
dc.subjectatomic processesen
dc.subjectline: formationen
dc.subjectquasars: absorptionen
dc.subjectlinesen
dc.subjectsun: abundancesen
dc.subjectism: atomsen
dc.subjectk-vacancy statesen
dc.subjectauger decay dataen
dc.subjectr-matrix methoden
dc.subjectoscillator-strengthsen
dc.subjectelectron-scatteringen
dc.subjectatomic structuresen
dc.subjectgeneralen
dc.subjectprogramen
dc.subjectlinesen
dc.subjectionsen
dc.subjectlifetimesen
dc.subjectastronomy & astrophysicsen
dc.titleRadiative transition rates and collision strengths for Si IIen
dc.title.serialAstronomy & Astrophysicsen
dc.typeArticle - Refereeden

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