EXTENDED ANALYSIS OF INTENSITY ANOMALIES IN THE AL-I ISOELECTRONIC SEQUENCE

This paper reports an extended experimental investigation, using the beam-foil technique, of the intensity ratio of the fine-structure components in the 3s(2)3p P-2(1/2, 3/2) 3s3p(2) S-2(1/2) and P-2(1/2) resonance transitions along the A1I isoelectronic sequence. These intensity ratios are strongly influenced by cancellation/enhancement effects arising from spin-orbit induced level mixings, and are thus sensitive probes of the detailed atomic structure. New data are given for Si II, P III, S IV, K VII, Sc IX, Fe XIV and Ni XVI. Together with previous experimental results this comprehensive isoelectronic study reveals significant and systematic deviations from theoretical predictions.