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Galaxies 2018, 6(3), 77; https://doi.org/10.3390/galaxies6030077

Successes and Difficulties in Calculating Atomic Oscillator Strengths and Transition Rates

Centre for Theoretical Atomic, Molecular and Optical Physics (CTAMOP), School of Mathematics & Physics, Queen’s University, Belfast BT7 1NN, Northern Ireland, UK
Received: 20 June 2018 / Revised: 17 July 2018 / Accepted: 18 July 2018 / Published: 24 July 2018
(This article belongs to the Special Issue Atomic and Molecular Data Needs for Astronomy and Astrophysics)
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Abstract

There is an on-going need for accurate oscillator strengths to be used in astrophysical applications, particularly in plasma diagnostics and in the modelling of stellar atmospheres and the interstellar medium. There are several databases in regular use which contain some of the required data, although often insufficiently complete, and sometimes not sufficiently accurate. In addition, several atomic structure packages are available through the literature, or from their individual authors, which would allow further calculations to be undertaken. Laboratory measurements provide an important check on the accuracy of calculated data, and the combined efforts of theorists and experimentalists have succeeded in providing data of an accuracy sufficient for some astrophysical applications. However, the insufficiency or inadequacy of atomic data is a continuing problem. We discuss in the context of appropriate examples some of the principal steps which researchers have taken to calculate accurate oscillator strengths, including both ab initio results and also various extrapolation processes which attempt to improve such results. We also present some examples of the main causes of difficulty in such calculations, particularly for complex (many-electron) ions, and indicate ways in which the difficulties might be overcome. View Full-Text
Keywords: E1 transitions; configuration interaction calculations; transition rates; remaining challenges to accuracy E1 transitions; configuration interaction calculations; transition rates; remaining challenges to accuracy
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
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Hibbert, A. Successes and Difficulties in Calculating Atomic Oscillator Strengths and Transition Rates. Galaxies 2018, 6, 77.

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