Abstract
Atomic data, such as wavelengths and line identifications, are necessary for many applications, especially in plasma diagnostics and for interpreting the spectra of distant astrophysical objects. The number of valence shell electrons increases the complexity of the computational problem. We have selected a five-electron ion, Na6+ (with the boron-like spectrum Na VII), for looking into the interplay of measurement and calculation. We summarize the available experimental work, perform our own extensive relativistic configuration interaction (RCI) computations based on multi-configuration Dirac–Hartree–Fock (MCDHF) wave functions, and compare the results to what is known of the level structure. We then discuss problems with databases that have begun to combine observations and computations.
Highlights
A good third of a century ago, the ground and low-lying displaced configuration levels of ions with an open n = 2 or n = 3 shell were calculated for survey and application purposes in the study ofAtoms 2015, 3 terrestrial and astrophysical plasmas
The calculations by Koc are based on a multireference relativistic configuration interaction (RCI) method with an orbital set based on analytical Gaussian functions
A detailed comparison of the present calculated energies and the experimental energies seems to indicate that there are some misidentifications, since for ten levels, the difference between calculated and experimental energies is 800 cm−1 or more. Disregarding these levels, the average relative difference between the calculated and experimental energy values is less than 0.018 %
Summary
A good third of a century ago, the ground and low-lying displaced configuration levels of ions with an open n = 2 or n = 3 shell were calculated for survey and application purposes in the study of. An example is the calculations by Fawcett [1,2], who used the non-relativistic Cowan code (Hartree–Fock with relativistic exchange (HXR)) to provide wavelengths and oscillator strengths on low-lying configurations of elements of astrophysics and fusion research interest. In these calculations, certain atomic structure parameters were scaled to fractions of their ab initio values in order to improve the agreement with experimental data. We have selected the extreme ultraviolet (EUV) spectrum of Na VII (B-like) for the purpose, for reasons that we detail below
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
