Anomalies in the beam-foil measurements for δn=o transitions in highly ionized members of the Li, Na, and Cu sequences

Systematic trends of absorption oscillator strengths for Δn=O transitions of the lithium, sodium, and coppper isoelectronic sequences have recently been established via agreement between theoretical calculations and benchmark beam-foil experiments. Although accurate mean lives have now been extracted from beam-foil decay curves, several anomalies have appeared. These are: 1) An unexpected sharp rise near foil zero in decay curves for the 2s ²S_1/2 - 2p ²b^{1/2 transition in Li-like titanium, iron, and krypton. 2) Unexplained intensity modulations in decay curves for Na-like nickel, copper, and bromine. 3) Unpredicted satellite lines that may be associated with the Δn=O transitions in Cu-like iodine. Possible origins and explanations for these apparent anomalies are discussed.}