Extended analysis of the Eu  III spectrum^*

¹ Laboratoire Aimé Cotton (CNRS UPR3321), bâtiment 505, Université Paris-Sud, 91405 Orsay Cedex, France
² Laboratoire d'Étude du Rayonnement et de la Matière en Astrophysique (LERMA), Observatoire de Paris-Meudon, Université Pierre et Marie Curie-Paris 6, 92190 Meudon, France e-mail: lydia.tchang-brillet@obspm.fr
³ Institute of Spectroscopy, Russian Academy of Sciences, 142190 Troitsk, Moscow region, Russia

Received: 27 December 2007
Accepted: 5 February 2008

Abstract

Aims. We create an Eu iii new atomic data set for interpreting the spectra of chemically peculiar stars by an extended analysis of the doubly-ionized europium.

Methods. We classified Eu iii spectral lines from a laboratory wavelength list with the support of energy and transition probability predictions in the Racah-Slater approach, using the Cowan codes and generalized least-squares fit (GLS) studies along the sequence of doubly-ionized lanthanides.

Results. More than thirty new levels and ninety classified lines are established in Eu iii. Improved prediction of the Eu iii  spectrum was achieved by using scaling factors for ab initio energy integrals, as well as effective configuration interaction parameters supplied by GLS studies. Transition probabilities, oscillator strengths, and Landé g-factors are calculated for the lines in the region 2000–9995 Å.