DATA-BASED PREDICTIONS OF LINE STRENGTHS IN ALKALI-METAL-LIKE ISOELECTRONIC-SEQUENCES

The empirically observed isoelectronic linearization of alkali-metal-like line strengths Z2S=A+B/(Z-C) is examined for the Li, Na, Cu, and Ag sequences. It is found that small deviations from this linearity observed at high Z can be removed by use of a correction factor obtained from the relativistic formulation of the hydrogenlike line strength. With this correction, low-Z data can be linearly interpolated to the nonrelativistic hydrogenic value in the high-Z limit. The linearization is tested in the data-rich Li, Na, and Cu sequences and is utilized to make precise predictions for the Ag sequence on the basis of a small number of accurate measurements. © 1995 The American Physical Society.