| 391. |
- Jönsson, Per, et al.
(författare)
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Special issue on critical assessment of theoretical calculations of atomic structure and transition probabilities
- 2013
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Ingår i: Atoms. - : MDPI. - 2218-2004. ; 1:2
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Tidskriftsartikel (refereegranskat)abstract
- There exist several codes in the atomic physics community to generate atomic structure and transition probabilities freely and readily distributed to researchers outside atomic physics community, in plasma, astrophysical or nuclear physics communities. Users take these atomic physics codes to generate the necessary atomic data or modify the codes for their own applications. However, there has been very little effort to validate and verify the data sets generated by non-expert users. In a recent IAEA meeting, researchers who develop the atomic physics codes met to discuss procedures to validate data sets generated by these distributed atomic physics codes. They agreed to implement and document the procedures to insure and validate code-generated data for non-experts in their codes. This special issue aims to document each code’s approach and procedure to critically assess the uncertainties of theoretical atomic data will have a broad impact, not only for the atomic physics community, but also for other communities interested in high quality atomic data.
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| 392. |
- Jönsson, Per, et al.
(författare)
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Spectral properties of InII from MCDHF calculations
- 2007
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 40:12, s. 2417-2433
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Tidskriftsartikel (refereegranskat)abstract
- We report extensive relativistic multiconfiguration Dirac-Hartree-Fock calculations of oscillator strengths and hyperfine structures for a large number of electric dipole transitions in In II. Results for the 5s(21)S(0)-5s5p P-3(0)o hyperfine induced transition are also presented. Core polarization is accounted for by means of explicit CI. To describe spin-polarization effects configuration state functions obtained by single excitations from all core-shells are included in the expansions. The computed oscillator strength for the 5s(2 1)S(0)-5s5p P-3(1)o intercombination transition is in good agreement with laser spectroscopy measurements of In+ ions in a radio-frequency trap. The calculated magnetic dipole hyperfine interaction constants agree very well with experimental constants derived from Fourier transform spectra. The problem with off-diagonal interactions affecting the hyperfine structures in closely spaced finestructure levels is discussed.
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| 393. |
- Jönsson, Per, et al.
(författare)
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Spectral properties of Sb IV from MCDHF calculations
- 2012
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Ingår i: Journal of Physics B. - : Bibliopolis, Edizioni di Filosofia e Scienze. - 0953-4075 .- 1361-6455. ; 45:16
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Tidskriftsartikel (refereegranskat)abstract
- We report on extensive relativistic multiconfiguration Dirac–Hartree–Fock (MCDHF) spectrum calculations for Sb IV. Energies, LS-compositions and Landé gJ-factors for 60 odd- and even-parity states are computed along with lifetimes and rates for transitions between these states. Results for the 5s2 1S0–5s5p 3Po0 hyperfine-induced transition are also presented. Valence and core-valence electron correlation effects are accounted for by explicit configuration interaction. The calculated energies agree very well with experiment, but the labelling of some of the odd states is ambiguous due to close degeneracies between the 5p5d, 5s7p and 5p6s configurations. Computed lifetimes of the excited states are compared with values from cascade-corrected beam-foil measurements.
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| 394. |
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| 395. |
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| 396. |
- Jönsson, Per, et al.
(författare)
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The ATSP2K and GRASP2K Multiconfiguration Atomic Structure Program Packages
- 2013
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Ingår i: Book of abstracts. - : Institute of Modern Physics, Chinese Academy of Sciences.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Synopsis The ATSP2K and GRASP2K program packages for large scale atomic calculations are presented. A number of applications are given to illustrate the potential and restriction of the packages.
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| 397. |
- Jönsson, Per, et al.
(författare)
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The Computational Atomic Structure Group : Code Development and Available Resources
- 2014
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Ingår i: Ninth International Conference on Atomic and Molecular Data and Their Applications: book of abstracts. ; , s. 113-113
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is an increasing demand for accurate atomic data due to advancements in experimental techniques and investments in large scale research facilities. In astrophysics the quality and resolution of solar and stellar spectra has so improved that the accuracy of atomic data is frequently a limiting factor in the interpretation. Accurate atomic data are also required in plasma physics and in other emerging areas such as laser spectroscopy on isotope separators, X-ray lithography, and lighting research. The needs include accurate transition energies, fine- and hyperfine structures, mass- and field shifts as well as parameters related to interaction with external magnetic fields. Also there is a constant need for transition rates of different multipolarities between excited states. Data are needed for a wide range of elements and ionization stages. To meet the demands for accurate atomic data the COMPutational Atomic Structure (COMPAS) group has been formed. The group is involved in developing state of the art computer codes for atomic structure calculations in the non-relativistic scheme with relativistic corrections in the Breit-Pauli approximation [1] as well as in the fully relativistic domain. Here we describe new developments of the GRASP2K relativistic atomic structure code [2,3]. We present results for a number of systems and properties to illustrate the potential and restriction of modern computational atomic structure. Among the properties are transition rates, hyperfine- and magnetically induced rates, energy structure, and isotope shifts. We also discuss current code developments and plans for future work. The codes developed by the COMPAS group, along with detailed user manuals, are freely available at http://ddwap.mah.se/tsjoek/compas/ .
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| 398. |
- Jönsson, Per, et al.
(författare)
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The grasp2K relativistic atomic structure package
- 2007
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Ingår i: Computer Physics Communications. - : Elsevier. - 0010-4655 .- 1879-2944. ; 177, s. 597-622
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes grasp2K, a general-purpose relativistic atomic structure package. It is a modification and extension of the GRASP92 package by [F.A. Parpia, C. Froese Fischer, I.P. Grant, Comput. Phys. Comm. 94 (1996) 249]. For the sake of continuity, two versions are included. Version 1 retains the GRASP92 formats for wave functions and expansion coefficients, but no longer requires preprocessing and more default options have been introduced. Modifications have eliminated some errors, improved the stability, and simplified interactive use. The transition code has been extended to cases where the initial and final states have different orbital sets. Several utility programs have been added. Whereas Version 1 constructs a single interaction matrix for all the J's and parities, Version 2 treats each J and parity as a separate matrix. This block structure results in a reduction of memory use and considerably shorter eigenvectors. Additional tools have been developed for this format. The CPU intensive parts of Version 2 have been parallelized using MPI. The package includes a “make” facility that relies on environment variables. These make it easier to port the application to different platforms. The present version supports the 32-bit Linux and ibmSP environments where the former is compatible with many Unix systems. Descriptions of the features and the program/data flow of the package will be given in some detail in this report.
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| 399. |
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| 400. |
- Jönsson, Per
(författare)
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Theoretical studies of hyperfine effects
- 2007
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Ingår i: Journal of Physics, Conference Series. - : Institute of Physics Publishing (IOPP). - 1742-6588 .- 1742-6596. ; 72:Conference Series 72
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Tidskriftsartikel (refereegranskat)abstract
- The development of space-based observatories has highlighted the need for atomic data. In this review we examine multiconfiguration methods for calculating these data. Particular emphasize is placed on hyperfine structure splittings and hyperfine induced transitions.
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