Effective L-shell fluorescence yields for sodiumlike and neonlike low-lying autoionizing states

The statistically averaged L-shell fluorescence yields for the doubly excited 3l3l’ and 3l4l’ configurations of Na- and Ne-like ions have been calculated for ions with 18≤Z≤92 using Dirac-Fock wave functions. The average n=3→2 radiative rates and Auger rates for the 3l3l’ states of the Na-like ions scale as Z^5.1 and Z^0.71, respectively. The procedure for calculating the average fluorescence yield as ratio between the average x-ray rate and average total decay rate underestimates the average fluorescence yield by as much as a factor of 3 for low-Z ions and overestimates by 50% for heavy ions. Inclusion of E2 transitions leads to a 25% increase in the average fluorescence yield for the Na-like 3l3l’ states at Z=80.