Eur. Phys. J. D 41, 211-219 (2007)
https://doi.org/10.1140/epjd/e2006-00229-5

Decay of metastable states in Nd II

¹ Astrophysique et Spectroscopie, Université de Mons-Hainaut, Rue de la Halle 15, 7000 Mons, Belgium
² IPNAS (Bât. B15), Université de Liège, 4000 Liège, Belgium
³ Physics Department, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
⁴ Physics Department, Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden

Corresponding author: ^a e.biemont@ulg.ac.be

Received: 18 February 2006
Revised: 20 September 2006
Published online: 13 October 2006

Abstract

The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements is illustrated in the case of Nd II. We have investigated the radiative decay of the low-lying metastable levels in Nd⁺ including the two levels K_11/2 and I_13/2. In these two particular cases, using different theoretical approaches, we find that the decay is dominated by the M1 channels but that the E2 contributions are of the same order of magnitude. These levels have also been studied experimentally by lifetime measurements with the heavy ion storage ring CRYRING of Stockholm University. The difficulties encountered when performing such experiments are underlined and discussed.