**Table 4:** Measured and calculated lifetimes for some of the lower levels in Fe XXIII. SS: calculated with SUPERSTRUCTURE and adjusted energies; AS: calculated with AUTOSTRUCTURE (Chidichimo et al. 2005); S99: calculated by Safronova et al. (1999) using relativistic many-body perturbation theory (including only n=2 levels).
i	Level	Measured	SS	AS	S99
3	2s 2p ³P $_{1}^{\rm o}$	17.5 $\pm$ 1.5^a (ns)	19.5	21.2	-
5	2s 2p ¹P $_{1}^{\rm o}$	51 $\pm$ 5^b (ps)	51.5	50.6	52.7
8	2p² ³P $_{2}^{\rm e}$	79 $\pm$ 8^b (ps)	76.8	75.2	76.2
9	2p² ¹D $_{2}^{\rm e}$	100 $\pm$ 8^b (ps)	102.2	104.3	108
10	2p² ¹S $_{0}^{\rm e}$	34 $\pm$ 5^b (ps)	32.0	31.6	32.3

^a Hutton et al. (1997).
^b Buchet et al. (1984).

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