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Spectrum of Ni V in the Vacuum Ultraviolet



Jacob W. Ward, A J. Raassen, Alexander Kramida, Gillian Nave


This work presents 97 remeasured Fe V wavelengths (1200 Å to 1600 Å) and 123 remeasured Ni V wavelengths (1200 Å to 1400 Å) with uncertainties of approximately 2 mÅ. An additional 67 remeasured Fe V wavelengths and 72 remeasured Ni V wavelengths with uncertainties greater than 2 mÅ are also reported. A systematic calibration error is also identified in the previous Ni V wavelengths and is corrected in this work. Furthermore, a new energy level optimization of Ni V is presented that includes level values as well as Ritz wavelengths. This work improves upon the available data used for observations of quadruply ionized nickel (Ni V) in white dwarf stars (Berengut et al. 2013). This compilation is specifically targeted towards observations of the G191-B2B white dwarf spectrum that has been used to test for variations in the fine structure constant, 𝛼, in the presence of strong gravitational fields (Berengut et al. 2013). The laboratory wavelengths for these ions were thought to be the cause of inconsistent conclusions regarding the variation limit of 𝛼 as observed through the white dwarf spectrum. These inconsistencies can now be addressed with the improved laboratory data presented here.
Astrophysical Journal


Atomic Spectroscopy, Laboratory Astrophysics, Nickel V, White Dwarf Stars


Ward, J. , Raassen, A. , Kramida, A. and Nave, G. (2019), Spectrum of Ni V in the Vacuum Ultraviolet, Astrophysical Journal, [online],, (Accessed June 21, 2024)


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Created November 27, 2019, Updated May 3, 2021