Jc. Pickering et al., Accurate laboratory wavelengths of some ultraviolet lines of Cr, Zn and Nirelevant to time variations of the fine structure constant, M NOT R AST, 319(1), 2000, pp. 163-167
The quality of astronomical spectroscopic data now available is so high tha
t interpretation and analysis are often limited by the uncertainties of the
laboratory data base. In particular, the limit with which space-time varia
tions in the fine structure constant alpha can be constrained using quasar
spectra depends on the availability of more accurate laboratory rest wavele
ngths. We recently measured some transitions in magnesium by high-resolutio
n Fourier transform spectroscopy for this purpose, and we now report measur
ements on some ultraviolet resonance lines of Zn II (2062 and 2026 Angstrom
), Cr II (2066, 2062 and 2056 Angstrom) and Ni II (1751, 1741, 1709 and 170
3 Angstrom). Apart from the last line, which is very weak, the uncertainty
of these measurements is 0.002 cm(-1) (0.08 m Angstrom) for the lines aroun
d 2000 Angstrom and 0.004 cm(-1) (0.12 m Angstrom) for the lines around 170
0 Angstrom.