A Systematic Study of Even Configurations in the Neutral Atoms of the Platinum Group

A systematic study of the even configurations 5 d N 6 s 2 , 5 d N +1 6 s and 5 d N +2 in neutral atoms of the platinum group has been performed by means of the parametric method. Consequently a number of empirical identifications of energy levels has been revised for Hf I, Ta I and Re I. In a generalized least squares fit 305 energy levels from Hf to Pt were interpreted by means of 59 parameters with a r.m.s. deviation of 122 cm -1 . An extrapolation towards lutecium has facilitated the theoretical interpretation of 8 low configurations in this element. The parametric study of 36 magnetic A hyperfine constants and 27 electric B constants has confirmed the labeling of the levels of Lu I.