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Radiative data for highly excited 3d 8 4d levels in Ni II from laboratory measurements and atomic calculations

Hartman, H. LU ; Engström, L. LU ; Lundberg, H. LU ; Nilsson, H. LU ; Quinet, P; Fivet, V; Palmeri, P; Malcheva, G and Blagoev, K (2017) In Astronomy and Astrophysics 600.
Abstract

Aims. This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d84d levels of astrophysical interest in singly ionized nickel. Methods. Radiative lifetimes of seven high-lying levels of even parity in Ni II (98 400-100 600 cm-1) have been measured using the time-resolved laser-induced fluorescence method. Two-step photon excitation of ions produced by laser ablation has been utilized to populate the levels. Theoretical calculations of the radiative lifetimes of the measured levels and transition probabilities from these levels are reported. The calculations have been performed using a pseudo-relativistic Hartree-Fock method, taking into account core... (More)

Aims. This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d84d levels of astrophysical interest in singly ionized nickel. Methods. Radiative lifetimes of seven high-lying levels of even parity in Ni II (98 400-100 600 cm-1) have been measured using the time-resolved laser-induced fluorescence method. Two-step photon excitation of ions produced by laser ablation has been utilized to populate the levels. Theoretical calculations of the radiative lifetimes of the measured levels and transition probabilities from these levels are reported. The calculations have been performed using a pseudo-relativistic Hartree-Fock method, taking into account core polarization effects. Results. A new set of transition probabilities and oscillator strengths has been deduced for 477 Ni II transitions of astrophysical interest in the spectral range 194-520 nm depopulating even parity 3d84d levels. The new calculated gf-values are, on the average, about 20% higher than a previous calculation and yield lifetimes within 5% of the experimental values.

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organization
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Contribution to journal
publication status
published
subject
keywords
Atomic data, Methods: laboratory: atomic, Techniques: spectroscopic
in
Astronomy and Astrophysics
volume
600
publisher
EDP Sciences
external identifiers
  • scopus:85017395371
  • wos:000400754000073
ISSN
0004-6361
DOI
10.1051/0004-6361/201629615
language
English
LU publication?
yes
id
fb1c69a0-140d-40a4-a348-f07e3601e92d
date added to LUP
2017-05-02 09:06:44
date last changed
2018-01-07 12:01:19
@article{fb1c69a0-140d-40a4-a348-f07e3601e92d,
  abstract     = {<p>Aims. This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d<sup>8</sup>4d levels of astrophysical interest in singly ionized nickel. Methods. Radiative lifetimes of seven high-lying levels of even parity in Ni II (98 400-100 600 cm<sup>-1</sup>) have been measured using the time-resolved laser-induced fluorescence method. Two-step photon excitation of ions produced by laser ablation has been utilized to populate the levels. Theoretical calculations of the radiative lifetimes of the measured levels and transition probabilities from these levels are reported. The calculations have been performed using a pseudo-relativistic Hartree-Fock method, taking into account core polarization effects. Results. A new set of transition probabilities and oscillator strengths has been deduced for 477 Ni II transitions of astrophysical interest in the spectral range 194-520 nm depopulating even parity 3d<sup>8</sup>4d levels. The new calculated gf-values are, on the average, about 20% higher than a previous calculation and yield lifetimes within 5% of the experimental values.</p>},
  articleno    = {A108},
  author       = {Hartman, H. and Engström, L. and Lundberg, H. and Nilsson, H. and Quinet, P and Fivet, V and Palmeri, P and Malcheva, G and Blagoev, K},
  issn         = {0004-6361},
  keyword      = {Atomic data,Methods: laboratory: atomic,Techniques: spectroscopic},
  language     = {eng},
  month        = {04},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {Radiative data for highly excited 3d <sup>8</sup> 4d levels in Ni II from laboratory measurements and atomic calculations},
  url          = {http://dx.doi.org/10.1051/0004-6361/201629615},
  volume       = {600},
  year         = {2017},
}