Advanced

Energy levels and transition rates for helium-like ions with Z = 10-36?

Si, R.; Guo, X. L.; Wang, K.; Li, S.; Yan, J.; Chen, C. Y.; Brage, T. LU and Zou, Y. M. (2016) In Astronomy and Astrophysics 592.
Abstract

Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate... (More)

Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate energies for the lowest singly excited 70 levels among 1snl (n ≤ 6; l ≤ (n - 1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln0l0 (n0 ≤ 6; l0 ≤ (n0 - 1)) configurations of helium-like ions with Z = 10-36.Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions. Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n = 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Atomic data, Atomic processes
in
Astronomy and Astrophysics
volume
592
publisher
EDP Sciences
external identifiers
  • scopus:84983336932
  • wos:000384722600145
ISSN
0004-6361
DOI
10.1051/0004-6361/201628656
language
English
LU publication?
yes
id
83407221-4ed4-4de7-937b-7c3dc983d7d1
date added to LUP
2016-12-16 15:31:12
date last changed
2017-09-18 11:31:46
@article{83407221-4ed4-4de7-937b-7c3dc983d7d1,
  abstract     = {<p>Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate energies for the lowest singly excited 70 levels among 1snl (n ≤ 6; l ≤ (n - 1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln0l0 (n0 ≤ 6; l0 ≤ (n0 - 1)) configurations of helium-like ions with Z = 10-36.Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions. Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n = 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics.</p>},
  articleno    = {A132},
  author       = {Si, R. and Guo, X. L. and Wang, K. and Li, S. and Yan, J. and Chen, C. Y. and Brage, T. and Zou, Y. M.},
  issn         = {0004-6361},
  keyword      = {Atomic data,Atomic processes},
  language     = {eng},
  month        = {08},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {Energy levels and transition rates for helium-like ions with Z = 10-36?},
  url          = {http://dx.doi.org/10.1051/0004-6361/201628656},
  volume       = {592},
  year         = {2016},
}