\begin{table}%t1
\caption{\label{tab_level}Energy levels (in Ryd) of Si$^{9+}$.}
\par
%\centering
\small
\begin{tabular}{lcccccc|lcccccc} 
\hline\hline
%&&&&&&&&&&&&& \\[-8pt]
{\rm ID} & {\rm Conf.} & $^{2S+1}L_J^{\pi}$ & ${\rm NIST}^a$
 & ${\rm AS}^b$  &  ${\rm FAC}^c$ & ${\rm ZS94}^d$ & {\rm ID} & {\rm Conf.} & $^{2S+1}L_J^{\pi}$ & ${\rm NIST}^a$
 & {\rm AS}  &  {\rm FAC} & {\rm ZS94} \\[2pt]
 \hline
%&&&&&&&&&&&&& \\[-8pt]
  1 & ${\rm   2s^2 2p}$ & ${\rm ^2P^{o}_{1/2} }$ &          &          &            &         &  64 & ${\rm   2p^2 3s}$ & ${\rm ^4P^{e}_{3/2} }$ &          & 20.8084  &  20.8434   & 20.7610 \\
  2 & ${\rm   2s^2 2p}$ & ${\rm ^2P^{o}_{3/2} }$ & 0.0637   & 0.0664   &   0.0623   &  0.0637 &  65 & ${\rm   2p^2 3s}$ & ${\rm ^4P^{e}_{5/2} }$ &          & 20.8453  &  20.8776   & 20.7951 \\
  3 & ${\rm   2s 2p^2}$ & ${\rm ^4P^{e}_{1/2} }$ & 1.4672   & 1.4370   &   1.4335   &  1.4672 &  66 & ${\rm 2s 2p 3d }$ & ${\rm ^2F^{o}_{7/2} }$ & 20.9582  & 21.0562  &  21.0263   & 21.0180 \\
  4 & ${\rm   2s 2p^2}$ & ${\rm ^4P^{e}_{3/2} }$ & 1.4898   & 1.4610   &   1.4567   &  1.4898 &  67 & ${\rm 2s 2p 3d }$ & ${\rm ^2F^{o}_{5/2} }$ & 20.9582  & 21.0575  &  21.0282   & 21.0191 \\
  5 & ${\rm   2s 2p^2}$ & ${\rm ^4P^{e}_{5/2} }$ & 1.5224   & 1.4985   &   1.4880   &  1.5224 &  68 & ${\rm 2s 2p 3d }$ & ${\rm ^2D^{o}_{3/2} }$ & 21.0551  & 21.1356  &  21.1353   & 21.0838 \\
  6 & ${\rm   2s 2p^2}$ & ${\rm ^2D^{e}_{3/2} }$ & 2.6231   & 2.6815   &   2.6620   &  2.6231 &  69 & ${\rm 2s 2p 3d }$ & ${\rm ^2D^{o}_{5/2} }$ & 21.0629  & 21.1425  &  21.1416   & 21.0900 \\
  7 & ${\rm   2s 2p^2}$ & ${\rm ^2D^{e}_{5/2} }$ & 2.6234   & 2.6833   &   2.6622   &  2.6234 &  70 & ${\rm   2p^2 3s}$ & ${\rm ^2P^{e}_{1/2} }$ &          & 21.2186  &  21.2463   & 21.1318 \\
  8 & ${\rm   2s 2p^2}$ & ${\rm ^2S^{e}_{1/2} }$ & 3.3505   & 3.4221   &   3.4029   &  3.3505 &  71 & ${\rm   2p^2 3s}$ & ${\rm ^2P^{e}_{3/2} }$ &          & 21.2590  &  21.2825   & 21.1699 \\
  9 & ${\rm   2s 2p^2}$ & ${\rm ^2P^{e}_{1/2} }$ & 3.5543   & 3.6491   &   3.6325   &  3.5543 &  72 & ${\rm 2s 2p 3d }$ & ${\rm ^2P^{o}_{1/2} }$ &          & 21.2731  &  21.2686   & 21.2200 \\
 10 & ${\rm   2s 2p^2}$ & ${\rm ^2P^{e}_{3/2} }$ & 3.5907   & 3.6895   &   3.6687   &  3.5907 &  73 & ${\rm 2s 2p 3d }$ & ${\rm ^2P^{o}_{3/2} }$ &          & 21.2800  &  21.2732   & 21.2246 \\
 11 & ${\rm      2p^3}$ & ${\rm ^4S^{o}_{3/2} }$ & 4.6414   & 4.6641   &   4.6274   &  4.6414 &  74 & ${\rm   2p^2 3p}$ & ${\rm ^2S^{o}_{1/2} }$ &          & 21.2878  &  21.3255   & 21.2422 \\
 12 & ${\rm      2p^3}$ & ${\rm ^2D^{o}_{3/2} }$ & 5.2437   & 5.3479   &   5.2973   &  5.2437 &  75 & ${\rm   2p^2 3p}$ & ${\rm ^4D^{o}_{1/2} }$ &          & 21.3792  &  21.4234   & 21.3370 \\
 13 & ${\rm      2p^3}$ & ${\rm ^2D^{o}_{5/2} }$ & 5.2439   & 5.3517   &   5.2984   &  5.2439 &  76 & ${\rm   2p^2 3p}$ & ${\rm ^4D^{o}_{3/2} }$ &          & 21.3931  &  21.4355   & 21.3510 \\
 14 & ${\rm      2p^3}$ & ${\rm ^2P^{o}_{1/2} }$ & 5.8937   & 6.0271   &   5.9806   &  5.8937 &  77 & ${\rm   2p^2 3p}$ & ${\rm ^4D^{o}_{5/2} }$ &          & 21.4168  &  21.4567   & 21.3744 \\
 15 & ${\rm      2p^3}$ & ${\rm ^2P^{o}_{3/2} }$ & 5.8994   & 6.0348   &   5.9832   &  5.8995 &  78 & ${\rm   2p^2 3s}$ & ${\rm ^2D^{e}_{5/2} }$ &          & 21.4443  &  21.4737   & 21.3951 \\
 16 & ${\rm   2s^2 3s}$ & ${\rm ^2S^{e}_{1/2} }$ &          & 16.5450  &  16.5368   & 16.4970 &  79 & ${\rm   2p^2 3s}$ & ${\rm ^2D^{e}_{3/2} }$ &          & 21.4455  &  21.4748   & 21.3956 \\
 17 & ${\rm   2s^2 3p}$ & ${\rm ^2P^{o}_{1/2} }$ &          & 17.2856  &  17.2881   & 17.2366 &  80 & ${\rm   2p^2 3p}$ & ${\rm ^4D^{o}_{7/2} }$ &          & 21.4503  &  21.4879   & 21.4061 \\
 18 & ${\rm   2s^2 3p}$ & ${\rm ^2P^{o}_{3/2} }$ &          & 17.3019  &  17.3046   & 17.2548 &  81 & ${\rm   2p^2 3p}$ & ${\rm ^4P^{o}_{1/2} }$ &          & 21.4860  &  21.5255   & 21.4449 \\
 19 & ${\rm   2s^2 3d}$ & ${\rm ^2D^{e}_{3/2} }$ & 18.0363  & 18.0030  &  17.9972   & 17.9443 &  82 & ${\rm   2p^2 3p}$ & ${\rm ^4P^{o}_{3/2} }$ &          & 21.4956  &  21.5349   & 21.4531 \\
 20 & ${\rm   2s^2 3d}$ & ${\rm ^2D^{e}_{5/2} }$ & 18.0406  & 18.0078  &  18.0014   & 17.9493 &  83 & ${\rm   2p^2 3p}$ & ${\rm ^4P^{o}_{5/2} }$ &          & 21.5166  &  21.5535   & 21.4733 \\
 21 & ${\rm 2s 2p 3s }$ & ${\rm ^4P^{o}_{1/2} }$ & 18.1600  & 18.1070  &  18.1088   & 18.0608 &  84 & ${\rm   2p^2 3p}$ & ${\rm ^2D^{o}_{3/2} }$ &          & 21.5945  &  21.6406   & 21.5462 \\
 22 & ${\rm 2s 2p 3s }$ & ${\rm ^4P^{o}_{3/2} }$ & 18.1810  & 18.1289  &  18.1293   & 18.0818 &  85 & ${\rm   2p^2 3p}$ & ${\rm ^2D^{o}_{5/2} }$ &          & 21.6397  &  21.6836   & 21.5903 \\
 23 & ${\rm 2s 2p 3s }$ & ${\rm ^4P^{o}_{5/2} }$ & 18.2215  & 18.1681  &  18.1675   & 18.1209 &  86 & ${\rm   2p^2 3p}$ & ${\rm ^4S^{o}_{3/2} }$ &          & 21.7785  &  21.8273   & 21.6973 \\
 24 & ${\rm 2s 2p 3s }$ & ${\rm ^2P^{o}_{1/2} }$ & 18.5084  & 18.4910  &  18.5012   & 18.4184 &  87 & ${\rm   2p^2 3p}$ & ${\rm ^2P^{o}_{3/2} }$ &          & 21.7866  &  21.8347   & 21.7384 \\
 25 & ${\rm 2s 2p 3s }$ & ${\rm ^2P^{o}_{3/2} }$ & 18.5521  & 18.5346  &  18.5431   & 18.4615 &  88 & ${\rm   2p^2 3p}$ & ${\rm ^2P^{o}_{1/2} }$ &          & 21.7908  &  21.8588   & 21.7342 \\
 26 & ${\rm 2s 2p 3p }$ & ${\rm ^4D^{e}_{1/2} }$ &          & 18.7682  &  18.7772   & 18.7209 &  89 & ${\rm   2p^2 3d}$ & ${\rm ^4F^{e}_{3/2} }$ &          & 21.9403  &  21.9761   & 21.8967 \\
 27 & ${\rm 2s 2p 3p }$ & ${\rm ^4D^{e}_{3/2} }$ &          & 18.7885  &  18.7954   & 18.7405 &  90 & ${\rm   2p^2 3d}$ & ${\rm ^4F^{e}_{5/2} }$ &          & 21.9537  &  21.9902   & 21.9094 \\
 28 & ${\rm 2s 2p 3p }$ & ${\rm ^2P^{e}_{1/2} }$ & 18.8139  & 18.8058  &  18.8146   & 18.7593 &  91 & ${\rm   2p^2 3d}$ & ${\rm ^4F^{e}_{7/2} }$ &          & 21.9731  &  22.0079   & 21.9278 \\
 29 & ${\rm 2s 2p 3p }$ & ${\rm ^2P^{e}_{3/2} }$ & 18.8336  & 18.8152  &  18.8238   & 18.7683 &  92 & ${\rm   2p^2 3d}$ & ${\rm ^4F^{e}_{9/2} }$ &          & 21.9993  &  22.0288   & 21.9520 \\
 30 & ${\rm 2s 2p 3p }$ & ${\rm ^4D^{e}_{5/2} }$ &          & 18.8220  &  18.8269   & 18.7769 &  93 & ${\rm   2p^2 3p}$ & ${\rm ^2F^{o}_{5/2} }$ &          & 22.0439  &  22.0825   & 22.0050 \\
 31 & ${\rm 2s 2p 3p }$ & ${\rm ^4D^{e}_{7/2} }$ &          & 18.8560  &  18.8607   & 18.8121 &  94 & ${\rm   2p^2 3p}$ & ${\rm ^2F^{o}_{7/2} }$ &          & 22.0554  &  22.0939   & 22.0171 \\
 32 & ${\rm 2s 2p 3p }$ & ${\rm ^4S^{e}_{3/2} }$ &          & 18.9487  &  18.9586   & 18.9056 &  95 & ${\rm   2p^2 3d}$ & ${\rm ^2P^{e}_{3/2} }$ &          & 22.0733  &  22.1139   & 22.0267 \\
 33 & ${\rm 2s 2p 3p }$ & ${\rm ^4P^{e}_{1/2} }$ &          & 19.0525  &  19.0822   & 18.9858 &  96 & ${\rm   2p^2 3d}$ & ${\rm ^4D^{e}_{1/2} }$ &          & 22.0776  &  22.1154   & 22.0355 \\
 34 & ${\rm 2s 2p 3p }$ & ${\rm ^4P^{e}_{3/2} }$ &          & 19.0711  &  19.0993   & 19.0046 &  97 & ${\rm   2p^2 3d}$ & ${\rm ^4D^{e}_{5/2} }$ &          & 22.0953  &  22.1334   & 22.0516 \\
 35 & ${\rm 2s 2p 3p }$ & ${\rm ^4P^{e}_{5/2} }$ &          & 19.0913  &  19.1179   & 19.0227 &  98 & ${\rm   2p^2 3d}$ & ${\rm ^4D^{e}_{3/2} }$ &          & 22.1032  &  22.1447   & 22.0571 \\
 36 & ${\rm 2s 2p 3p }$ & ${\rm ^2D^{e}_{3/2} }$ & 19.1890  & 19.1704  &  19.1919   & 19.1028 &  99 & ${\rm   2p^2 3d}$ & ${\rm ^4D^{e}_{7/2} }$ &          & 22.1066  &  22.1403   & 22.0621 \\
 37 & ${\rm 2s 2p 3p }$ & ${\rm ^2D^{e}_{5/2} }$ & 19.2301  & 19.2114  &  19.2327   & 19.1437 & 100 & ${\rm   2p^2 3d}$ & ${\rm ^2P^{e}_{1/2} }$ &          & 22.1345  &  22.1755   & 22.0831 \\
 38 & ${\rm 2s 2p 3d }$ & ${\rm ^4F^{o}_{3/2} }$ &          & 19.3897  &  19.3973   & 19.3414 & 101 & ${\rm   2p^2 3d}$ & ${\rm ^2F^{e}_{5/2} }$ &          & 22.1703  &  22.2021   & 22.1259 \\
 39 & ${\rm 2s 2p 3d }$ & ${\rm ^4F^{o}_{5/2} }$ &          & 19.4030  &  19.4121   & 19.3544 & 102 & ${\rm   2p^2 3d}$ & ${\rm ^2F^{e}_{7/2} }$ &          & 22.2179  &  22.2450   & 22.1725 \\
 40 & ${\rm 2s 2p 3d }$ & ${\rm ^4F^{o}_{7/2} }$ &          & 19.4226  &  19.4318   & 19.3738 & 103 & ${\rm   2p^2 3d}$ & ${\rm ^4P^{e}_{5/2} }$ & 22.2756  & 22.2494  &  22.2927   & 22.1978 \\
 41 & ${\rm 2s 2p 3p }$ & ${\rm ^2S^{e}_{1/2} }$ & 19.4337  & 19.4284  &  19.4463   & 19.3548 & 104 & ${\rm   2p^2 3p}$ & ${\rm ^2D^{o}_{5/2} }$ &          & 22.2642  &  22.3481   & 22.1825 \\
 42 & ${\rm 2s 2p 3d }$ & ${\rm ^4F^{o}_{9/2} }$ &          & 19.4499  &  19.4548   & 19.4014 & 105 & ${\rm   2p^2 3d}$ & ${\rm ^4P^{e}_{3/2} }$ & 22.2896  & 22.2649  &  22.3069   & 22.2135 \\
 43 & ${\rm 2s 2p 3d }$ & ${\rm ^4D^{o}_{1/2} }$ & 19.6004  & 19.5602  &  19.5722   & 19.5081 & 106 & ${\rm   2p^2 3p}$ & ${\rm ^2D^{o}_{3/2} }$ &          & 22.2651  &  22.3514   & 22.1856 \\
 44 & ${\rm 2s 2p 3d }$ & ${\rm ^4D^{o}_{3/2} }$ & 19.6004  & 19.5622  &  19.5757   & 19.5096 & 107 & ${\rm   2p^2 3d}$ & ${\rm ^4P^{e}_{1/2} }$ &          & 22.2731  &  22.3158   & 22.2216 \\
 45 & ${\rm 2s 2p 3d }$ & ${\rm ^4D^{o}_{5/2} }$ & 19.6046  & 19.5664  &  19.5820   & 19.5130 & 108 & ${\rm   2p^2 3s}$ & ${\rm ^2S^{e}_{1/2} }$ &          & 22.4339  &  22.4660   & 22.4001 \\
 46 & ${\rm 2s 2p 3d }$ & ${\rm ^4D^{o}_{7/2} }$ & 19.6271  & 19.5879  &  19.5997   & 19.5349 & 109 & ${\rm   2p^2 3p}$ & ${\rm ^2P^{o}_{1/2} }$ &          & 22.4519  &  22.5090   & 22.3612 \\
 47 & ${\rm 2s 2p 3d }$ & ${\rm ^2D^{o}_{3/2} }$ & 19.6260  & 19.6072  &  19.6198   & 19.5313 & 110 & ${\rm   2p^2 3p}$ & ${\rm ^2P^{o}_{3/2} }$ &          & 22.4792  &  22.5387   & 22.3865 \\
 48 & ${\rm 2s 2p 3d }$ & ${\rm ^2D^{o}_{5/2} }$ & 19.6331  & 19.6112  &  19.6240   & 19.5390 & 111 & ${\rm   2p^2 3d}$ & ${\rm ^2D^{e}_{3/2} }$ &          & 22.5927  &  22.6130   & 22.5328 \\
 49 & ${\rm 2s 2p 3d }$ & ${\rm ^4P^{o}_{5/2} }$ & 19.6917  & 19.6450  &  19.6568   & 19.5923 & 112 & ${\rm   2p^2 3d}$ & ${\rm ^2D^{e}_{5/2} }$ &          & 22.5934  &  22.6147   & 22.5347 \\
 50 & ${\rm 2s 2p 3d }$ & ${\rm ^4P^{o}_{3/2} }$ & 19.7025  & 19.6516  &  19.6655   & 19.6026 & 113 & ${\rm   2p^2 3d}$ & ${\rm ^2G^{e}_{7/2} }$ &          & 22.6011  &  22.6272   & 22.5608 \\
 51 & ${\rm 2s 2p 3d }$ & ${\rm ^4P^{o}_{1/2} }$ &          & 19.6576  &  19.6736   & 19.6098 & 114 & ${\rm   2p^2 3d}$ & ${\rm ^2G^{e}_{9/2} }$ &          & 22.6062  &  22.6303   & 22.5653 \\
 52 & ${\rm 2s 2p 3s }$ & ${\rm ^2P^{o}_{1/2} }$ &          & 19.7078  &  19.7031   & 19.6708 & 115 & ${\rm   2p^2 3d}$ & ${\rm ^2D^{e}_{3/2} }$ &          & 22.7474  &  22.7877   & 22.7047 \\
 53 & ${\rm 2s 2p 3s }$ & ${\rm ^2P^{o}_{3/2} }$ & 19.6682  & 19.7092  &  19.7045   & 19.6714 & 116 & ${\rm   2p^2 3d}$ & ${\rm ^2D^{e}_{5/2} }$ &          & 22.7651  &  22.8000   & 22.7200 \\
 54 & ${\rm 2s 2p 3d }$ & ${\rm ^2F^{o}_{5/2} }$ & 19.9439  & 19.9522  &  19.9611   & 19.9023 & 117 & ${\rm   2p^2 3d}$ & ${\rm ^2F^{e}_{7/2} }$ &          & 22.8084  &  22.8288   & 22.7608 \\
 55 & ${\rm 2s 2p 3d }$ & ${\rm ^2F^{o}_{7/2} }$ & 19.9858  & 19.9925  &  19.9999   & 19.9430 & 118 & ${\rm   2p^2 3d}$ & ${\rm ^2F^{e}_{5/2} }$ &          & 22.8222  &  22.8440   & 22.7754 \\
 56 & ${\rm 2s 2p 3d }$ & ${\rm ^2P^{o}_{3/2} }$ & 20.0407  & 20.0350  &  20.0399   & 19.9648 & 119 & ${\rm   2p^2 3d}$ & ${\rm ^2P^{e}_{1/2} }$ &          & 22.9527  &  22.9918   & 22.8744 \\
 57 & ${\rm 2s 2p 3d }$ & ${\rm ^2P^{o}_{1/2} }$ & 20.0642  & 20.0575  &  20.0621   & 19.9866 & 120 & ${\rm   2p^2 3d}$ & ${\rm ^2P^{e}_{3/2} }$ &          & 22.9693  &  23.0067   & 22.8888 \\
 58 & ${\rm 2s 2p 3p }$ & ${\rm ^2P^{e}_{1/2} }$ &          & 20.4168  &  20.4263   & 20.3749 & 121 & ${\rm   2p^2 3d}$ & ${\rm ^2S^{e}_{1/2} }$ &          & 23.0395  &  23.0746   & 23.0057 \\
 59 & ${\rm 2s 2p 3p }$ & ${\rm ^2P^{e}_{3/2} }$ &          & 20.4271  &  20.4346   & 20.3836 & 122 & ${\rm   2p^2 3p}$ & ${\rm ^2P^{o}_{1/2} }$ &          & 23.1746  &  23.2319   & 23.1418 \\[2pt]
\hline
 60 & ${\rm 2s 2p 3p }$ & ${\rm ^2D^{e}_{3/2} }$ &          & 20.4412  &  20.4468   & 20.3963 & 123 & ${\rm   2p^2 3p}$ & ${\rm ^2P^{o}_{3/2} }$ &          & 23.1805  &  23.2360   & 23.1486 \\
 61 & ${\rm 2s 2p 3p }$ & ${\rm ^2D^{e}_{5/2} }$ &          & 20.4424  &  20.4463   & 20.3977 & 124 & ${\rm   2p^2 3d}$ & ${\rm ^2D^{e}_{5/2} }$ &          & 23.7640  &  23.7756   & 23.7376 \\
 62 & ${\rm 2s 2p 3p }$ & ${\rm ^2S^{e}_{1/2} }$ & 20.4698  & 20.6368  &  20.6169   & 20.5801 & 125 & ${\rm   2p^2 3d}$ & ${\rm ^2D^{e}_{3/2} }$ &          & 23.7716  &  23.7839   & 23.7456 \\
 63 & ${\rm   2p^2 3s}$ & ${\rm ^4P^{e}_{1/2} }$ &          & 20.7850  &  20.8237   & 20.7382 &     &                 &                      &          &          &            &         \\[2pt]
\hline
\end{tabular}
\medskip
$^{a}$ \url{http://physics.nist.gov/PhysRefData/ASD/levels_form.html};
$^{b}$ {\sc autostructure} (present work);
$^{c}$ Liang et~al. (\cite{LZZ07}); 
$^{d}$ Zhang \& Sampson (\cite{ZS94}), their 15~lowest-lying levels are observed values from Zhang et~al. (\cite{ZGP94}).
\end{table}