Atomic oscillator-strength distributions in spectral series of the lithium isoelectronic sequence

Abstract

We describe a new type of analysis yielding the oscillator-strength distributions in several spectral series throughout the lithium isoelectronic sequence. Individual oscillator strengths have been critically evaluated and tied together by requiring that they fulfill simultaneously four basic spectroscopic constraints: (a) regularities for individual transitions along the isoelectronic sequence, (b) regularities for the transitions of a spectral series, (c) compliance with the requirement of continuity across the spectral series limit, and (d) adherence to $f$ sum rules. With only slight modifications, the best available data fulfill closely all four requirements. The final set of $f$-value data—which are tabulated and partly presented in illustrations—possess, therefore, a very high degree of internal consistency and reliability. Relativistic corrections for very highly charged Li-like ions are also considered.