Berlin 2001 – scientific programme
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A: Atomphysik
A 17: Posters Friday (Spectroscopy)
A 17.5: Poster
Friday, April 6, 2001, 12:30–15:00, AT3
Parametric analysis and ab initio calculations of isotope shifts in neutral and singly-ionized nickel — •Michel Godefroid1, Abdelilah Yousfi1, Jacques Bauche2, and Charlotte Froese Fischer3 — 1Lab. Chim. Phys. Molec, U.L.B., Brussels, Belgium — 2Lab. Aime-Cotton, CNRS, Orsay, France — 3Dpt of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, USA
The first part of our work concerns the semi-empirical calculation of isotope shifts in Ni I. Two independent parametric studies of energy levels have been completed [1,2]. We combine the resulting intermediate coupling eigenvectors with the Vinti integrals and electron densities calculated in the Hartree-Fock approximation using an adaptation of Cowan’s codes. The isotope level shifts are extracted from the measured transition isotope shifts [1] for the 58-60,60-62 and 58-64 isotopic pairs and studied through a Bauche and Champeau parametric analysis. We also report results of an ab initio approach of Ni II considering the isotope shifts of the 3d74s2 2G − 3d84p 4Go and 3d9 2D − 3d8 4p 2Fo lines. For the first transition, experimental isotope shifts have been measured [3] and can be used for comparison while for the latter, a theoretical estimation of the specific mass shift contribution was needed to evaluate its effect on the curve of growth of the spectral line [4]. [1] U. Litzén, J.W. Brault and A.P. Thorne, Physica Scripta 47 (1993) 628. [2] R.L. Kurucz, ASP Conference Series 81 (1995) 583. [3] M. Rosberg, U. Litzén and S. Johansson, Mon. Not. R. Astron. Soc. 262 (1993) L1. [4] J.A. Fedchak, L.M. Wiese and J.E. Lawler, ApJ 538 (2000) 773