| 1. |
- Guo, Xueling, et al.
(författare)
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Energy levels and radiative data for Kr-like W38+ from MCDHF and RMBPT calculations
- 2016
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 49:13
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Tidskriftsartikel (refereegranskat)abstract
- Energies, transition rates, line strengths and lifetimes have been computed for all levels of the 4p 6 and 4p 54d configurations of W38+ by using the multi-configuration Dirac-Hartree-Fock (MCDHF) method as well as relativistic many-body perturbation theory. We investigate systematically correlation, relativistic and quantum electro-dynamical (QED) effects of different properties, including excitation energies and transition rates. We demonstrate that it is important to include the core-valence correlation of rather deep subshells (including 3d and 3p) to reach close to spectroscopic accuracy for the transition energies. We also show that high-multipole transitions (E3, M2) are important for the lifetime of some metastable levels of 4p 54d (). The present results are in good agreement with experiments and of considerably higher accuracy than those achieved in previous theoretical works.
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| 2. |
- Si, Ran, et al.
(författare)
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EXTENDED CALCULATIONS WITH SPECTROSCOPIC ACCURACY : ENERGY LEVELS AND TRANSITION PROPERTIES FOR THE FLUORINE-LIKE ISOELECTRONIC SEQUENCE WITH Z = 24–30
- 2016
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 227:2
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Tidskriftsartikel (refereegranskat)abstract
- We have performed extensive multiconfiguration Dirac–Hartree–Fock calculations and second-order many-body perturbation calculations for F-like ions with Z = 24–30. Energy levels and transition rates for electric dipole (E1), electric-quadrupole (E2), electricoctupole (E3), magnetic dipole (M1), and magnetic-quadrupole (M2) transitions, as well as radiative lifetimes, are provided for the lowest 200 levels belonging to the 1s22s22p5, 1s22s2p6, 1s22s22p43l, 1s22s2p53l, 1s22p63l, and 1s22s22p44l configurations of each ion. The results from the two sets of calculations are in excellent agreement. Extensive comparisons are also made with other theoretical results and observed data from the CHIANTI and NIST databases. The present energies and wavelengths are believed to be accurate enough to aid line identifications involving the n = 3 and n = 4 configurations, for which observations are largely missing. The calculated wavelengths and transition data will be useful in the modeling and diagnostics of astrophysical and fusion plasmas.
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| 3. |
- Wang, Kai, et al.
(författare)
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Benchmarking Atomic Data for Astrophysics : Be-like Ions between B II and Ne VII
- 2018
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Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 234:2
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale self-consistent multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations are reported for the n <= 6 levels in Be-like ions from B II to Ne VII. Effects from electron correlation are taken into account by means of large expansions in terms of a basis of configuration state functions, and a complete and accurate data set of excitation energies; lifetimes; wavelengths; electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole line strengths; transition rates; and oscillator strengths for these levels is provided for each ion. Comparisons are made with available experimental and theoretical results. The uncertainty of excitation energies is assessed to be 0.01% on average, which makes it possible to find and rule out misidentifications and aid new line identifications involving high-lying levels in astrophysical spectra. The complete data set is also useful for modeling and diagnosing astrophysical plasmas.
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| 4. |
- Wang, Kai, et al.
(författare)
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Calculations with spectroscopic accuracy for energies, transition rates, hyperfine interaction constants, and Landé gJ-factors in nitrogen-like Kr XXX
- 2017
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 187, s. 375-402
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Tidskriftsartikel (refereegranskat)abstract
- Extensive self-consistent multi-configuration Dirac-Fock(MCDF) calculations and second-order many- body perturbation theory (MBPT) calculations are performed for the lowest 272 states belonging to the 2s22p3, 2s2p4, 2p5, 2s22p23l, and2s2p33l (l¼s, p, d) configurations of N-like KrXXX.Complete and consistent datasets of level energies,wavelengths,line strengths, oscillator strengths,lifetimes, AJ, BJ hyperfine interaction constants,Landé gJ-factors, and electric dipole(E1),magnetic dipole(M1),electric quadrupole(E2),magnetic quadrupole(M2) transition rates among all these levels are given.The present MCDF and MBPTresults are compared with each other and with other available experimental and theoretical results.The mean relative difference between our two sets of level energies is only about 0.003% for these 272 levels.The accuracy of the present calculations are high enough to facilitate identification of many observed spectral lines.These accurate data can be served as benchmark for other calculations and can be useful for fusion plasma research and astrophysical applications.
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| 5. |
- Wang, Kai, et al.
(författare)
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EXTENDED RELATIVISTIC CONFIGURATION INTERACTION AND MANY-BODY PERTURBATION CALCULATIONS OF SPECTROSCOPIC DATA FOR THE N 6 CONFIGURATIONS IN Ne-LIKE IONS BETWEEN Cr XV AND Kr XXVII
- 2016
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 226:2
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Tidskriftsartikel (refereegranskat)abstract
- Level energies, wavelengths, electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transition rates, oscillator strengths, and line strengths from combined relativistic con guration interaction and many-body perturbation calculations are reported for the 201 ne-structure states of the 2s22p6, 2s22p53l, 2s2p63l, 2s22p54l, 2s2p64l, 2s22p55l, and 2s22p56l con gurations in all Ne-like ions between Cr XV and Kr XXVII. Calculated level energies and transition data are compared with experiments from the National Institute of Standards and Technology (NIST) and CHIANTI databases, and other recent benchmark calculations. The mean energy difference with the NIST experiments is only 0.05%. The present calculations signi cantly increase the amount of accurate spectroscopic data for the n > 3 states in a number of Ne-like ions of astrophysical interest. A complete data set should be helpful for analyzing new observations from solar and other astrophysical sources, and is also likely to be useful for modeling and diagnosing a variety of plasmas, including astronomical and fusion plasma.
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| 6. |
- Wang, Kai, et al.
(författare)
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Large-scale Multiconfiguration Dirac-Hartree-Fock and Relativistic Configuration Interaction Calculations of Transition Data for B-like S XII
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 864:2
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Tidskriftsartikel (refereegranskat)abstract
- Excitation energies and lifetimes for the 213 lowest states of the n <= 5 configurations in B-like S XII are calculated using highly correlated wave functions, optimized with the fully relativistic multiconfiguration Dirac-Hartree-Fock method. Multipole transition rates and associated radiative data (line strengths and oscillator strengths) for transitions connecting these levels are also reported. The theoretical excitation energies are systematically compared with the NIST Atomic Spectra Database in which misidentifications are pointed out. After eliminating the latter, a mean energy difference with the standard deviation between computed and observed energies of 12 +/- 341 cm(-1) is obtained for the n >= 3 high-lying states. This level of accuracy confirms that elaborate ab initio calculations can assist in the identification of new emission lines in the solar and other astrophysical spectra. The present work provides atomic data of high accuracy for an ion of astrophysical interest, B-like S XII, for which experimental data are scarce.
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| 7. |
- Zhang, Chun Yu, et al.
(författare)
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Benchmarking calculations of wavelengths and transition rates with spectroscopic accuracy for W XLVIII through W LVI tungsten ions
- 2022
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 105:2
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Tidskriftsartikel (refereegranskat)abstract
- Atomic properties of n = 3 levels for W47+ - W55+ ions (Z = 74) are systematically calculated using two different and independent methods, namely, the second-order many-body perturbation theory and the multi-configuration Dirac-Hartree-Fock method combined with the relativistic configuration interaction approach. Wavelengths and transition rates for electric-and magnetic-dipole transitions involving the n = 3 levels of W47+ - W55+ are calculated. In addition, we discuss in detail the importance of the valence and core-valence electron correlations, the Breit interaction, the higher-order frequency-dependent retardation correction, and the leading quantum electrodynamical corrections for transition wavelengths. Spectroscopic accuracy is achieved for the present calculated wavelengths, and most of them agree with experimental values within 0.05%. Our calculated wavelengths, combined with collisional radiative model simulations, are used to identify the yet unidentified 25 observed lines in the extremely complex spectrum between 27 angstrom and 34 angstrom measured by Lennartsson et al. [Phys. Rev. A 87, 062505 (2013)]. We provide additional data for 472 strong electric-dipole transitions in the wavelength range of 17-50 angstrom, and 185 strong magnetic-dipole transitions between 36 angstrom and 4384 angstrom, with a line intensity greater than 1 photon/s. These can provide benchmark data for future experiments and theoretical calculations.
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