EXPERIMENTAL AND THEORETICAL DECAY-RATES OF CORE-EXCITED QUARTET LEVELS IN NA-LIKE S-VI AND CI-VII

Experimental lifetimes of quartet levels in the 2p(5)3p2 and 2p(5)3s3d core-excited configurations in Na-like S VI and Cl VII have been measured using the beam-foil method. A theoretical study of the different decay modes of the quartet levels, using the superposition-of-configurations method including continuum channels, is also reported. A comparison of the experimental and theoretical total decay rates shows good qualitative agreement, but also that the theoretical predictions underestimate the lifetimes by typically 50%. Larger discrepancies are found for quartet levels predicted to have a significant autoionization rate.