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Lego Figure holding a lego telescope. Photo

Henrik Hartman

Researcher (Leave of Absence)

Lego Figure holding a lego telescope. Photo

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

Author

  • H. Hartman
  • L. Engström
  • H. Lundberg
  • H. Nilsson
  • P Quinet
  • V Fivet
  • P Palmeri
  • G Malcheva
  • K Blagoev

Summary, in English

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.

Department/s

  • Lund Observatory - Has been reorganised
  • Department of Physics

Publishing year

2017-04-01

Language

English

Publication/Series

Astronomy and Astrophysics

Volume

600

Document type

Journal article

Publisher

EDP Sciences

Topic

  • Atom and Molecular Physics and Optics

Keywords

  • Atomic data
  • Methods: laboratory: atomic
  • Techniques: spectroscopic

Status

Published

ISBN/ISSN/Other

  • ISSN: 0004-6361