\begin{table}%t2[!htbp]
\caption{The details of the  most important configurations in 
\ion{Fe}{xxiii} (only the most significant $n=4$ levels 
are shown; the full Table is available in electronic form). 
The percentage of level mixing ($>$10\%) is indicated
in second column.
$E_{\rm best}$ indicates the best energies (\cm)
which we propose in this work.
The uncertainties in the energies reflect the 
estimated errors in the wavelength measurements.
Levels with uncertain identification are assigned 
an uncertainty of 5000~\cm, 
an estimate based on the comparisons between the 
observed energies and the values computed \mbox{ab initio}.
The other columns indicate the differences between  our 
$E_{\rm best}$ and the energies from NIST $E_{\rm NIST}$, the collisional 
calculations $E_{\rm CC}$, and the adjusted SS values $E_{\rm SS}$. 
Levels are ordered according to the 
energies $E_{\rm CC}$ from the scattering calculations.
\label{tab:levels}}
%\centering
\par
%\scriptsize
\footnotesize
%\tiny
%\normalsize
\begin{tabular}[c]{@{}rlcrrrrr@{}}
\hline\hline\noalign{\smallskip}
%\begin{longtable}{@{}|rlcrrrrr|@{}}
 $i$ &  Configuration (\% purity) & Term & $E_{\rm best}$ & $E_{\rm  best}{-}E_{\rm NIST}$ & $E_{\rm best}{-}E_{\rm CC}$  &  $E_{\rm  best}{-}E_{\rm SS}$  & \\ 
\noalign{\smallskip}\hline\noalign{\smallskip}
%  fe_23_45conf_TEC_be_IC.out.el.tex 
% 
%45configurations included: \\
%Calculated: 15/Aug/04 17:29:17 \\
%
1 & 2s$^2$(95\%) & $^1$S$_{0}^{\rm e}$ &          0.0 $\pm$ 0 & 0 & $+$0 & 0  &  \\
2 & 2s 2p(99\%) & $^3$P$_{0}^{\rm o}$ &     348~100.0 $\pm$ 800 & $-80$ & $+$2393 & $+230$  &  \\
3 & 2s 2p(97\%) & $^3$P$_{1}^{\rm o}$ &     379~125.0 $\pm$ 10 & $-5$ & $+$1432 & $+164$  &  \\
4 & 2s 2p(99\%) & $^3$P$_{2}^{\rm o}$ &     471~768.0 $\pm$ 10 & $-12$ & $+$2647 & $-146$  &  \\
\par
5 & 2s 2p(97\%) & $^1$P$_{1}^{\rm o}$ &     752~410.0 $\pm$ 100 & $-430$ & $-4029$ & $-157$  &  \\
6 & 2p$^2$(93\%) & $^3$P$_{0}^{\rm e}$ &     956~100.0 $\pm$ 500 & 0 & $+2129$ & $+836$  &  \\
7 & 2p$^2$(99\%) & $^3$P$_{1}^{\rm e}$ &    1~027~200.0 $\pm$ 500 & 0 & $+4005$ & $+787$  &  \\
8 & 2p$^2$(73\%) $+9(26\%)$ & $^3$P$_{2}^{\rm e}$ &    1~071~700.0 $\pm$ 500 & 0 & $+$31 & $+$306  &  \\
9 & 2p$^2$(73\%) $+8(26\%)$ & $^1$D$_{2}^{\rm e}$ &    1~204~200.0 $\pm$ 500 & 0 & $-$936 & $-$975  &  \\
10 & 2p$^2$(89\%) & $^1$S$_{0}^{\rm e}$ &    1~422~600.0 $\pm$ 800 & $-400$ & $-$4489 & $-$346  &  \\
11 & 2s 3s(98\%) & $^3$S$_{1}^{\rm e}$ &    8~913~200.0 $\pm$ 2000 & 19~200 & $-$6191 & $-$3  &  \\
12 & 2s 3s(97\%) & $^1$S$_{0}^{\rm e}$ &    8~975~300.0 $\pm$ 1000 &  --  & $-$15~841 & $-$7  &  \\
13 & 2s 3p(62\%) $+15(33\%)$ & $^3$P$_{1}^{\rm o}$ &    9~076~060.0 $\pm$ 1000 & 60 & $-$9648 & $+$688  &  \\
14 & 2s 3p(98\%) & $^3$P$_{0}^{\rm o}$ &    9~075~227.0 $\pm$ 5000 &  --  & $-$10~572 & 0  &  \\
15 & 2s 3p(57\%) +13(35\%) & $^1$P$_{1}^{\rm o}$ &    9~107~500.0 $\pm$ 1000 & 500 & $-$8552 & $-$128  &  \\
16 & 2s 3p(98\%) & $^3$P$_{2}^{\rm o}$ &    9~112~000.0 $\pm$ 2000 &  --  & $-$7424 & $+$450  &  \\
17 & 2s 3d(97\%) & $^3$D$_{1}^{\rm e}$ &    9~198~400.0 $\pm$ 2000 & $-600$ & $-$10~950 & $+$1031  &  \\
18 & 2s 3d(98\%) & $^3$D$_{2}^{\rm e}$ &    9~200~000.0 $\pm$ 3000 & $-9000$ & $-$14~241 & $-$2453  &  \\
19 & 2s 3d(99\%) & $^3$D$_{3}^{\rm e}$ &    9~211~300.0 $\pm$ 2000 & $-700$ & $-$10~669 & $+$695  &  \\
20 & 2s 3d(97\%) & $^1$D$_{2}^{\rm e}$ &    9~272~500.0 $\pm$ 2000 & $-500$ & $-$13~635 & $-$28  &  \\
21 & 2p 3s(98\%) & $^3$P$_{0}^{\rm o}$ &    9~348~070.0 $\pm$ 5000 & 53~070 & $-$10~861 & 0  &  \\
22 & 2p 3s(82\%) $+25(13\%)$ & $^3$P$_{1}^{\rm o}$ &    9~365~642.0 $\pm$ 5000 &  --  & $-$11~236 & 0  &  \\
23 & 2p 3p(67\%) $+27(28\%)$ & $^3$D$_{1}^{\rm e}$ &    9~458~199.0 $\pm$ 5000 & 3199 & $-$8828 & 0  &  \\
24 & 2p 3s(98\%) & $^3$P$_{2}^{\rm o}$ &    9~476~500.0 $\pm$ 3000 &  --  & $-$3051 & $+$3874  &  \\
25 & 2p 3s(77\%) $+22(16\%)$ & $^1$P$_{1}^{\rm o}$ &    9~518~800.0 $\pm$ 3000 & 48~800 & $-$8653 & $-$85  &  \\
26 & 2p 3p(83\%) & $^3$D$_{2}^{\rm e}$ &    9~524~000.0 $\pm$ 1000 & 0 & $-$8026 & $-$465  &  \\
27 & 2p 3p(27\%) $+23(19\%)$ +30(25\%) +33(26\%) & $^1$P$_{1}^{\rm e}$ &    9~525~633.0 $\pm$ 5000 &  --  & $-$7578 & 0  &  \\
28 & 2p 3p(88\%) $+44(10\%)$ & $^3$P$_{0}^{\rm e}$ &    9~544~996.0 $\pm$ 5000 &  --  & $-$11~834 & 0  &  \\
29 & 2p 3d(77\%) $+39(19\%)$ & $^3$F$_{2}^{\rm o}$ &    9~583~144.0 $\pm$ 5000 &  --  & $-$7710 & 0  &  \\
30 & 2p 3p(46\%) $+23(11\%)$ $+27(36\%)$ & $^3$P$_{1}^{\rm e}$ &    9~615~925.0 $\pm$ 5000 &  --  & $-$5665 & 0  &  \\
31 & 2p 3p(99\%) & $^3$D$_{3}^{\rm e}$ &    9~623~400.0 $\pm$ 1000 & $-600$ & $-$3804 & $+$293  &  \\
32 & 2p 3d(78\%) $+40(13\%)$ & $^3$F$_{3}^{\rm o}$ &    9~624~600.0 $\pm$ 1000 & $-400$ & $-$9504 & $-$2112  &  \\
33 & 2p 3p(64\%) $+30(27\%)$ & $^3$S$_{1}^{\rm e}$ &    9~640~640.0 $\pm$ 5000 &  --  & $-$5515 & 0  &  \\
34 & 2p 3d(27\%) $+39(33\%)$ +41(30\%) & $^3$D$_{2}^{\rm o}$ &    9~637~500.0 $\pm$ 3000 & $-500$ & $-$9234 & $-$2177  &  \\
35 & 2p 3p(62\%) $+26(14\%)$ +37(22\%) & $^3$P$_{2}^{\rm e}$ &    9~643~700.0 $\pm$ 2000 & $-300$ & $-$6343 & $+$463  &  \\
36 & 2p 3d(69\%) $+42(16\%)$ +46(13\%) & $^3$D$_{1}^{\rm o}$ &    9~663~000.0 $\pm$ 3000 & 26~000 & $-$3720 & $+$4435  &  \\
37 & 2p 3p(67\%) $+35(30\%)$ & $^1$D$_{2}^{\rm e}$ &    9~708~000.0 $\pm$ 1000 & $-1000$ & $-$4806 & $+$154  &  \\
38 & 2p 3d(99\%) & $^3$F$_{4}^{\rm o}$ &    9~719~900.0 $\pm$ 2000 &  --  & $-$1989 & $+$1625  &  \\
39 & 2p 3d(42\%) $+29(14\%)$ $+34(32\%)$ & $^1$D$_{2}^{\rm o}$ &    9~728~150.0 $\pm$ 3000 & 150 & $-$4037 & $+$45  &  \\
40 & 2p 3d(75\%) $+32(18\%)$ & $^3$D$_{3}^{\rm o}$ &    9~753~000.0 $\pm$ 2000 & 4000 & $-$4889 & $-$840  &  \\
41 & 2p 3d(56\%) $+34(37\%)$ & $^3$P$_{2}^{\rm o}$ &    9~772~700.0 $\pm$ 2000 & 19~700 & $-$4447 & $-$861  &  \\
42 & 2p 3d(75\%) $+36(22\%)$ & $^3$P$_{1}^{\rm o}$ &    9~773~832.0 $\pm$ 5000 &  --  & $-$3995 & 0  &  \\
43 & 2p 3d(98\%) & $^3$P$_{0}^{\rm o}$ &    9~776~004.0 $\pm$ 5000 &  --  & $-$4118 & 0  &  \\
44 & 2p 3p(86\%) $+28(11\%)$ & $^1$S$_{0}^{\rm e}$ &    9~786~485.0 $\pm$ 5000 &  --  & $-$6166 & 0  &  \\
45 & 2p 3d(86\%) $+40(10\%)$ & $^1$F$_{3}^{\rm o}$ &    9~829~000.0 $\pm$ 4000 & $-1000$ & $-$11~612 & $-$2041  &  \\
46 & 2p 3d(84\%) & $^1$P$_{1}^{\rm o}$ &    9~844~520.0 $\pm$ 5000 & 16~520 & $-$5716 & 0  &  \\
\hline
47 & 2s 4s(99\%) & $^3$S$_{1}^{\rm e}$ &   11~955~378.0 $\pm$ 5000 &  --  & $-$17~747 & 0  &  \\
48 & 2s 4s(98\%) & $^1$S$_{0}^{\rm e}$ &   11~980~800.0 $\pm$ 2000 &  --  & $-$15~429 & $-$7  &  \\
49 & 2s 4p(99\%) & $^3$P$_{0}^{\rm o}$ &   12~021~399.0 $\pm$ 5000 &  --  & $-$14~649 & 0  &  \\
50 & 2s 4p(84\%) +52(15\%) & $^3$P$_{1}^{\rm o}$ &   12~026~500.0 $\pm$ 3000 &  --  & $-$11~253 & $+$2971  &  \\
51 & 2s 4p(99\%) & $^3$P$_{2}^{\rm o}$ &   12~037~223.0 $\pm$ 5000 &  --  & $-$12~358 & 0  &  \\
52 & 2s 4p(83\%) +50(15\%) & $^1$P$_{1}^{\rm o}$ &   12~044~000.0 $\pm$ 5000 & 0 & $-$10~558 & $+$312  &  \\
53 & 2s 4d(99\%) & $^3$D$_{1}^{\rm e}$ &   12~073~000.0 $\pm$ 2000 & 0 & $-$14~052 & $-$1307  &  \\
54 & 2s 4d(98\%) & $^3$D$_{2}^{\rm e}$ &   12~075~000.0 $\pm$ 2000 & 0 & $-$13~720 & $-$1147  &  \\
55 & 2s 4d(99\%) & $^3$D$_{3}^{\rm e}$ &   12~080~800.0 $\pm$ 2000 & $-200$ & $-$10~894 & $+$1228  &  \\
56 & 2s 4d(98\%) & $^1$D$_{2}^{\rm e}$ &   12~098~000.0 $\pm$ 2000 & 0 & $-$13606 & $-$45  &  \\
\par
%57 & 2s 4f(99\%) & $^3$F$_{2}^{\rm o}$ &   12101948.0 $\pm$ 5000 &  --  & $-$13658 & 0  &  \\
%58 & 2s 4f(96\%) & $^3$F$_{3}^{\rm o}$ &   12102789.0 $\pm$ 5000 &  --  & $-$13624 & 0  &  \\
%59 & 2s 4f(99\%) & $^3$F$_{4}^{\rm o}$ &   12104408.0 $\pm$ 5000 &  --  & $-$13513 & 0  &  \\
%60 & 2s 4f(96\%) & $^1$F$_{3}^{\rm o}$ &   12109346.0 $\pm$ 5000 &  --  & $-$13648 & 0  &  \\
%61 & 2p 4s(99\%) & $^3$P$_{0}^{\rm o}$ &   12360689.0 $\pm$ 5000 &  --  & $-$17868 & 0  &  \\
%62 & 2p 4s(71\%) +75(27\%) & $^3$P$_{1}^{\rm o}$ &   12365910.0 $\pm$ 5000 &  --  & $-$17533 & 0  &  \\
%63 & 2p 4p(70\%) +77(26\%) & $^3$D$_{1}^{\rm e}$ &   12411938.0 $\pm$ 5000 &  --  & $-$13050 & 0  &  \\
%64 & 2p 4p(43\%) +63(13\%) +77(14\%) +80(28\%) & $^3$P$_{1}^{\rm e}$ &   12439943.0 $\pm$ 5000 &  --  & $-$10661 & 0  &  \\
%65 & 2p 4p(61\%) +79(23\%) +81(14\%) & $^3$D$_{2}^{\rm e}$ &   12442211.0 $\pm$ 5000 &  --  & $-$10167 & 0  &  \\
%66 & 2p 4p(78\%) +85(20\%) & $^3$P$_{0}^{\rm e}$ &   12444085.0 $\pm$ 5000 &  --  & $-$11385 & 0  &  \\
%67 & 2p 4d(76\%) +83(18\%) & $^3$F$_{2}^{\rm o}$ &   12462454.0 $\pm$ 5000 &  --  & $-$12625 & 0  &  \\
\par
68 & 2p 4d(28\%) +86(19\%) +71(c14 39\%) & $^3$P$_{2}^{\rm o}$ &   12~480~600.0 $\pm$ 3000 & $-400$ & $-$10041 & $+$1054  &  \\
69 & 2p 4d(59\%) +95(19\%) +84(20\%) & $^3$F$_{3}^{\rm o}$ &   12~483~300.0 $\pm$ 3000 & $-700$ & $-$12~052 & $-$464  &  \\
70 & 2p 4d(58\%) +87(17\%) +97(23\%) & $^3$D$_{1}^{\rm o}$ &   12~487~500.0 $\pm$ 3000 & $-500$ & $-$13~429 & $-$3926  &  \\
71 & 2p 4s(59\%) +86(c16 14\%) +68(c16 14\%) & $^3$P$_{2}^{\rm o}$ &   12~491~100.0 $\pm$ 3000 &  --  & $-$13~170 & $-$1628  &  \\
\par
%72 & 2p 4f(70\%) +89(21\%) & $^3$G$_{3}^{\rm e}$ &   12494215.0 $\pm$ 5000 &  --  & $-$12243 & 0  &  \\
%73 & 2p 4f(51\%) +98(19\%) +91(28\%) & $^3$F$_{2}^{\rm e}$ &   12497545.0 $\pm$ 5000 &  --  & $-$12248 & 0  &  \\
%74 & 2p 4f(48\%) +92(33\%) +89(16\%) & $^3$D$_{3}^{\rm e}$ &   12498552.0 $\pm$ 5000 &  --  & $-$12059 & 0  &  \\
%75 & 2p 4s(71\%) +62(27\%) & $^1$P$_{1}^{\rm o}$ &   12498344.0 $\pm$ 5000 &  --  & $-$12522 & 0  &  \\
%76 & 2p 4f(41\%) +94(29\%) +90(28\%) & $^3$G$_{4}^{\rm e}$ &   12498819.0 $\pm$ 5000 &  --  & $-$12270 & 0  &  \\
%77 & 2p 4p(45\%) +63(16\%) +64(38\%) & $^1$P$_{1}^{\rm e}$ &   12547334.0 $\pm$ 5000 &  --  & $-$8136 & 0  &  \\
\par
78 & 2p 4p(99\%) & $^3$D$_{3}^{\rm e}$ &   12~559~300.0 $\pm$ 3000 & $-700$ & $-$2910 & $+$3016  &  \\
79 & 2p 4p(24\%) +65(36\%) +81(39\%) & $^1$D$_{2}^{\rm e}$ &   12~559~300.0 $\pm$ 3000 &  --  & $-$3208 & $+$4276  &  \\
\par
%80 & 2p 4p(67\%) +64(18\%) +77(13\%) & $^3$S$_{1}^{\rm e}$ &   12558986.0 $\pm$ 5000 &  --  & $-$8573 & 0  &  \\
%81 & 2p 4p(46\%) +79(51\%) & $^3$P$_{2}^{\rm e}$ &   12581426.0 $\pm$ 5000 &  --  & $-$5641 & 0  &  \\
%82 & 2p 4d(99\%) & $^3$F$_{4}^{\rm o}$ &   12592832.0 $\pm$ 5000 &  --  & $-$8539 & 0  &  \\
\par
83 & 2p 4d(54\%) +67(19\%) +86(23\%) & $^1$D$_{2}^{\rm o}$ &   12~597~000.0 $\pm$ 3000 & 0 & $-$4381 & $+$1317  &  \\
84 & 2p 4d(58\%) +69(35\%) & $^3$D$_{3}^{\rm o}$ &   12~603~000.0 $\pm$ 3000 & 0 & $-$6401 & $+$211  &  \\
\par
%85 & 2p 4p(78\%) +66(21\%) & $^1$S$_{0}^{\rm e}$ &   12610141.0 $\pm$ 5000 &  --  & $-$5034 & 0  &  \\
\par
86 & 2p 4d(39\%) +68(51\%) & $^3$D$_{2}^{\rm o}$ &   12~614~000.0 $\pm$ 3000 & 0 & $-$3081 & $+$1881  &  \\
87 & 2p 4d(70\%) +70(27\%) & $^3$P$_{1}^{\rm o}$ &   12~615~000.0 $\pm$ 3000 & 0 & $-$2092 & $+$3250  &  \\
\par
%88 & 2p 4d(99\%) & $^3$P$_{0}^{\rm o}$ &   12612796.0 $\pm$ 5000 &  --  & $-$5364 & 0  &  \\
%89 & 2p 4f(39\%) +72(27\%) +92(32\%) & $^1$F$_{3}^{\rm e}$ &   12616997.0 $\pm$ 5000 &  --  & $-$7796 & 0  &  \\
%90 & 2p 4f(66\%) +76(32\%) & $^3$F$_{4}^{\rm e}$ &   12619812.0 $\pm$ 5000 &  --  & $-$7706 & 0  &  \\
%91 & 2p 4f(17\%) +73(46\%) +98(36\%) & $^1$D$_{2}^{\rm e}$ &   12623881.0 $\pm$ 5000 &  --  & $-$7610 & 0  &  \\
%92 & 2p 4f(26\%) +89(22\%) +74(50\%) & $^3$F$_{3}^{\rm e}$ &   12624597.0 $\pm$ 5000 &  --  & $-$7478 & 0  &  \\
%93 & 2p 4f(99\%) & $^3$G$_{5}^{\rm e}$ &   12626054.0 $\pm$ 5000 &  --  & $-$7498 & 0  &  \\
%94 & 2p 4f(68\%) +76(26\%) & $^1$G$_{4}^{\rm e}$ &   12628145.0 $\pm$ 5000 &  --  & $-$7866 & 0  &  \\
\par
95 & 2p 4d(73\%) +84(21\%) & $^1$F$_{3}^{\rm o}$ &   12~630~000.0 $\pm$ 3000 & $-1000$ & $-$7211 & $-$987  &  \\
96 & 2p 4f(99\%) & $^3$D$_{1}^{\rm e}$ &   12~630~996.0 $\pm$ 5000 &  --  & $-$7341 & 0  &  \\
97 & 2p 4d(75\%) +70(13\%) +87(11\%) & $^1$P$_{1}^{\rm o}$ &   12~638~236.0 $\pm$ 5000 &  --  & $-$3686 & 0  &  \\
98 & 2p 4f(43\%) +91(54\%) & $^3$D$_{2}^{\rm e}$ &   12~635~506.0 $\pm$ 5000 &  --  & $-$7186 & 0  &  \\
\hline
\end{tabular}
\normalsize
%\label{tab:levels}
%Table~\ref{tab:levels}
\end{table}