\begin{table}%t2
\par
\caption{Levels of the atomic model explicitly treated in NLTE by COSI. The columns denote the ion, level, atomic number AN, electron configuration and spectroscopic term designation, the ionization wavelength $\lambda_{{\rm ion}}$ calculated from the measured energies from the NIST database, where * detotes ionization to an excited state of the next higher ion, the ionization potential $E_{{\rm ion}}$ of the ground state, the weighted mean of the level energy $E$, the statistical weight $g$ of the model configuration, and the source of the photoionization cross sections.\label{tab:levels}}
\small%\centering
\par
\begin{tabular}{lrrllrrrrl}
\hline\hline\noalign{\smallskip}
      Ion  & 
      Level  &
      AN  & 
      Configuration &
      Term & 
      $\lambda_{{\rm ion}}$ (\AA)&  
      $E_{{\rm ion}}$ (${\rm cm^{-1}}$) &
      $E$ (${\rm cm^{-1}}$)&
      ${g}$&
      {{Source}}\\  
\hline
 \noalign{\smallskip}
H$^{-}$&1&1&${\rm 1s}$&${\rm ^{1}S}$&16~414.54&6090.50&0.0&2&J88$^1$\\
H~{\sc{i}}&1&1&${\rm 1s}$&${\rm ^{2}S}$&911.77&109~677.38&0.0&2&MIH$^2$ \\
H~{\sc{i}}&2&1&${\rm 2p}$&${\rm ^{2}P^{\circ}}$ &  3645.49   &  & 82~258.04 	& 8 & MIH \\
H~{\sc{i}}&3&1&${\rm 2s}$  & ${\rm ^{2}S}$         &  8200.65   &  & 97~491.00	& 18 & MIH \\
H~{\sc{i}}&4&1&${\rm 3p}$  & ${\rm ^{2}P^{\circ}}$ & 14~576.68   &  & 102~822.54	& 32 & MIH \\
H~{\sc{i}}&5&1&${\rm 3s}$  & ${\rm ^{2}S}$         & 22~773.63   &  & 105~290.28       & 50 & MIH \\
H~{\sc{i}}&6&1&${\rm 3d}$  & ${\rm ^{2}D}$         & 32~791.60   &  & 106~630.79	& 72 & MIH \\
H~{\sc{i}}&7&1&${\rm 4p}$  & ${\rm ^{2}P^{\circ}}$ & 44~630.70   &  & 107~439.07	& 98 & MIH \\
H~{\sc{i}}&8&1&${\rm 4s}$  & ${\rm ^{2}S}$         & 58~291.00   &  & 107~963.67	& 128 & MIH \\
H~{\sc{i}}&9&1&${\rm 4d}$  & ${\rm ^{2}D}$         & 73~772.54   &  & 108~323.34 	& 162 & MIH \\
H~{\sc{i}}&10&1&${\rm 4f}$ & ${\rm ^{2}P^{\circ}}$ & 91~075.35   &  & 108~580.61	& 200 & MIH \\
H~{\sc{ii}}&1&1&--       & --  &         &  & 0.0 	& 1 & -- \\
He~{\sc{i}}&1&2&${\rm 1s^2}$& ${\rm ^{1}S}$ &   504.25    				& 8200.65  & 0.0 	& 1 &  KOE$^3$\\
He~{\sc{i}}&2&2&${\rm 1s2s}$ & ${\rm ^{3}S}$ &  2601.00    				&  & 159~856.07	& 3 &  KOE\\
He~{\sc{i}}&3&2&${\rm 1s2s}$ & ${\rm ^{1}S}$ &  3122.27    				&  & 166~277.55	& 1 &  KOE\\
He~{\sc{i}}&4&2&${\rm 1s2p}$ & ${\rm ^{3}P^{\circ}}$ &  3422.37    &  & 169~086.94 	& 7 &  KOE\\
He~{\sc{i}}&5&2&${\rm 1s2p}$ & ${\rm ^{1}P^{\circ}}$ &  3680.26    &  & 171~135.00	& 3 &  KOE\\
He~{\sc{i}}&6&2&${\rm 1s3s}$ & ${\rm ^{3}S}$ &  6634.61    &  & 183~236.89	& 3 &  KOE\\
He~{\sc{i}}&7&2&${\rm 1s3s}$ & ${\rm ^{1}S}$ &  7437.69    &  & 184~864.55	& 1 &  KOE\\
He~{\sc{i}}&8&2&${\rm 1s3p}$ & ${\rm ^{3}P^{\circ}}$ &  7846.22    &  & 185~564.68	& 7 &  KOE\\
He~{\sc{i}}&9&2&${\rm 1s3d}$ & ${\rm ^{3}D}$ &  8191.29    &  & 186~101.65	& 13&  KOE\\
He~{\sc{i}}&10&2&${\rm 1s3d}$ & ${\rm ^{1}D}$ &  8193.59    &  & 186~105.07  & 5 &  KOE\\
He~{\sc{ii}}&1&2&${\rm 1s}$  & ${\rm ^{2}S}$ &        			&   438~908.85& 0.0 		& 2 &  --\\
Li~{\sc{i}}&1&3&[He]${\rm 2s}$   & ${\rm ^{2}S}$ &   2298.90      & 43~487.15& 0.0 	& 2 & Hyd$^4$\\
Li~{\sc{ii}}&1&3& [He]       	        & ${\rm ^{1}S}$ &       &       & 0.0 		& 1 & -- \\
Be~{\sc{i}}&1&4& [He]${\rm 2s^2}$ & ${\rm ^{1}S}$ &   1329.92     & 75~192.64& 0.0 	& 1 & Hyd\\
Be~{\sc{ii}}&1&4& [He]${\rm 2s}$   & ${\rm ^{2}S}$ &               &        & 0.0 	& 2 &  -- \\
B~{\sc{i}}&1&5& [He]${\rm 2s^2 2p}$ & ${\rm ^{2}P^{\circ}}$ & 1494.14 & 66~928.10& 0.0 	& 2 & Hyd\\
B~{\sc{ii}}&1&5& [He]${\rm 2s^2}$    & ${\rm ^{1}S}$ &  & & 0.0 			& 1 &  -- \\
C~{\sc{i}}&1&6& [He]${\rm 2s^2 2p^2}$ & ${\rm ^{3}P}$ & 1101.79& 90~820.42&  29.57	& 9 & OP$^5$\\
C~{\sc{i}}&2&6& [He]${\rm 2s^2 2p^2}$ & ${\rm ^{1}D}$ & 1240.72& 			& 10~192.63 & 5& OP\\
C~{\sc{i}}&3&6& [He]${\rm 2s^2 2p^2}$ & ${\rm ^{1}S}$ & 1446.28&			& 21~648.01 & 1& OP\\       
C~{\sc{ii}}&1& 6&[He]${\rm 2s^2 2p}$& ${\rm ^{2}P^{\circ}}$&	&		& 0.00 &6& -- \\ 
N~{\sc{i}}&1&7& [He]${\rm 2s^2 2p^3}$  & ${\rm ^{4}S^{\circ}}$ & 852.62 & 117~314.58& 0.0 & 4& Hyd \\
N~{\sc{ii}}&1&7& [He]${\rm 2s^2 2p^2}$  & ${\rm ^{3}P}$         &  & & 0.0 		        & 9 & -- \\
O~{\sc{i}}&1&8& [He]${\rm 2s^2 2p^4}$  & ${\rm ^{3}P}$         &  911.73& 109~837.02& 77.97 	& 9 &  Hyd\\
O~{\sc{ii}}&1&8& [He]${\rm 2s^2 2p^3}$ & ${\rm ^{4}S^{\circ}}$  &  & & 0.0 		& 4 & -- \\
F~{\sc{i}}&1&9& [He]${\rm 2s^2 2p^5}$  & ${\rm ^{3}P^{\circ}}$ &  712.99& 140~524.5 & 134.7  & 6 & Hyd\\
F~{\sc{ii}}&1&9& [He]${\rm 2s^2 2p^4}$ & ${\rm ^{3}P}$          &  & & 0.0 			& 9 & -- \\
Ne~{\sc{i}}&1&10& [He]${\rm 2s^2 2p^6}$  & ${\rm ^{1}S}$       &  574.94&  173~929.75&  	& 1 &  Hyd\\
Ne~{\sc{ii}}&1&10& [He]${\rm 2s^2 2p^5}$ & ${\rm ^{2}P^{\circ}}$ &  & & 0.0 	& 6 & --\\
Na~{\sc{i}}&1&11&[Ne]${\rm 3s}$  & ${\rm ^{2}S}$&2411.91&41~449.62& 0.00 &2 & OP\\
Na~{\sc{i}}&2&11&[Ne]${\rm 3p}$  & ${\rm ^{2}P^{\circ}}$&4083.51& & 16~967.64&6 & OP\\
Na~{\sc{i}}&3&11&[Ne]${\rm 4s}$   & ${\rm ^{2}S}$&6363.72 & & 25~739.99&2 & OP\\ 
Na~{\sc{i}}&4&11&[Ne]${\rm 3d}$   & ${\rm ^{2}D}$& 8143.14& & 29~172.86&10 & OP\\ 
Na~{\sc{i}}&5&11&[Ne]${\rm 4p}$   & ${\rm ^{2}P^{\circ}}$&8942.85 & & 30~270.72&6 & OP\\ 
Na~{\sc{i}}&6&11&[Ne]${\rm 5s}$   & ${\rm ^{2}S}$&12~119.24 & & 33~200.68&2 & OP\\
Na~{\sc{i}}&7&11&[Ne]${\rm 4d}$   & ${\rm ^{2}D}$&14~486.66 & & 34~548.74&10 & OP\\ 
Na~{\sc{i}}&8&11&[Ne]${\rm 4f}$   & ${\rm ^{2}F^{\circ}}$&14~567.25 & & 34~586.92&14 & OP\\ Na~{\sc{i}}&9&11&[Ne]${\rm 5p}$   & ${\rm ^{2}P^{\circ}}$&15~601.91 & & 35~042.03&6 & OP\\ 
Na~{\sc{i}}&10&11&[Ne]${\rm 6s}$  & ${\rm ^{2}S}$&19~690.85  & & 36~372.62&2 & OP\\ 
Na~{\sc{ii}}&1 & 11&[Ne]          &  ${\rm ^{1}S}$&  & & 0.00 &1& --\\    
Mg~{\sc{i}}&1& 12&[Ne]${\rm 3s^2}$& ${\rm ^{1}S}$	&  1621.51&  61~671.02&0.00 &1 & OP\\
Mg~{\sc{i}}&2&12&[Ne]${\rm 3s3p}$  & ${\rm ^{3}P^{\circ}}$&  2512.26& & 21~877.30  &9 & OP\\
Mg~{\sc{i}}&3&  12&[Ne]${\rm 3s3p}$  &  ${\rm ^{1}P^{\circ}}$& 3755.50& & 35~051.26& 3   & OP\\ 
Mg~{\sc{ii}}&1&  12&[Ne]${\rm 3s}$ &  ${\rm ^{2}S}$&  & & 0.00 &2 & --\\    
Al~{\sc{i}}&1& 13&[Ne]${\rm 3s^2 3p}$&${\rm ^{2}P}^{\circ}$& 2077.19& 48~278.20& 74.71 & 6 & OP\\ 
Al~{\sc{ii}}&1&  13&[Ne]${\rm 3s^2}$ & ${\rm ^{1}S}$&  && 0.00 & 1  & -- \\    
Si~{\sc{i}}&1& 14&[Ne]${\rm 3s^2 3p^2}$		&${\rm ^{3}P}$&1527.92& 65~747.76&   149.68 & 9 & OP\\ 
Si~{\sc{i}}&2& 14&[Ne]${\rm 3s^2 3p^2}$   &  ${\rm ^{1}D}$& 1686.36&  &  6298.85 & 5&  OP\\  
Si~{\sc{i}}&3& 14&[Ne]${\rm 3s^2 3p^2}$   &  ${\rm ^{1}S}$ & 1991.88&  &  15~394.37 & 1 & OP\\   
\hline
Si~{\sc{i}}&4&14 &[Ne]${\rm 3s 3p^3}$     &  ${\rm ^{5}S^{\circ}}$ & *~1328.47 & & 33~326.04 & 5  & OP\\      
Si~{\sc{i}}&5& 14&[Ne]${\rm 3s^2 3p4s}$   &   ${\rm ^{3}P^{\circ}}$&   3875.02& & 39~799.50  & 9 & OP\\
Si~{\sc{i}}&6& 14&[Ne]${\rm 3s^2 3p4s}$   &   ${\rm ^{1}P^{\circ}}$&    4062.78&& 40~991.88 & 3& OP\\ 
Si~{\sc{ii}}&1&  14&[Ne]${\rm 3s^2(^1S)3p}$ &   ${\rm ^{2}P^{\circ}}$&  &&   0.00& 6 &  --\\
S~{\sc{i}}&1& 16&[Ne]${\rm 3s^2 3p^4}$& ${\rm ^{3}P}$& 1199.85&  83~559.10& 107.74 &9 & OP\\
S~{\sc{i}}&2&16&[Ne]${\rm 3s^2 3p^4}$&${\rm ^{1}D}$  & 1347.48&		 & 9238.61&5& OP\\
S~{\sc{i}}&3&16&[Ne]${\rm 3s^2 3p^4}$  & ${\rm ^{1}S}$&1632.08& 	 & 22~179.95&1& OP\\   
S~{\sc{ii}}&1& 16&[Ne]${\rm 3s^2 3p^3}$  & ${\rm ^{4}S^{\circ}}$&  & & 0.00 &4 & -- \\    
P~{\sc{i}}&1&15& [Ne]${\rm 3s^2 3p^3}$ & ${\rm ^{4}S^{\circ}}$ & 1182.30 &  84~580.83& 0.0 & 4 &  Hyd\\
P~{\sc{ii}}&1&15& [Ne]${\rm 3s^2 3p^2}$ & ${\rm ^{3}P}$         &  & & 0.0 		    & 9 & -- \\
Cl~{\sc{i}}&1&17& [Ne]${\rm 3s^2 3p^5}$  & ${\rm ^2P^{\circ}}$ &961.51  & 104~591.0 & 0.0& 6 & Hyd\\
Cl~{\sc{ii}}&1&17& [Ne]${\rm 3s^2 3p^4}$  & ${\rm ^3P}$ &  &  & 0.0& 9 & -- \\
Ar~{\sc{i}}&1&18& [Ne]${\rm 3s^2 3p^6}$ & ${\rm ^1 S}$ &786.72 & 127~109.80 & 0.0 & 1 &Hyd \\
Ar~{\sc{ii}}&1&18& [Ne]${\rm 3s^2 3p^5}$ & ${\rm ^2P^{\circ}}$ &  &    & 0.0 & 6 & -- \\
K~{\sc{i}}&1& 19&[Ar]${\rm 4s}$ &${\rm ^{2}S}$	&  2855.56&  35~009.81&    0.00 &2 &  Hyd\\
K~{\sc{i}}&2& 19&[Ar]${\rm 4p}$ &${\rm ^{2}P^{\circ}}$& 4547.06&  & 13~023.64&6 & Hyd\\
K~{\sc{i}}&3& 19&[Ar]${\rm 5s}$ &${\rm ^{2}S}$& 7149.41& & 21~026.55& 2   & Hyd\\ 
K~{\sc{i}}&4& 19&[Ar]${\rm 3d}$ &${\rm ^{2}D}$&   7419.51& & 21~535.60&10   & Hyd\\ 
K~{\sc{i}}&5& 19&[Ar]${\rm 5p}$ &${\rm ^{2}P^{\circ}}$&   9709.85& & 24~713.90& 6   & Hyd\\ 
K~{\sc{i}}&6& 19&[Ar]${\rm 4d}$ &${\rm ^{2}D}$&  13~132.87& & 27~397.50&10   & Hyd\\ 
K~{\sc{i}}&7& 19&[Ar]${\rm 6s}$ &${\rm ^{2}S}$&13~225.32& & 27~450.71& 2   & Hyd\\ 
K~{\sc{i}}&8& 19&[Ar]${\rm 4f}$ &${\rm ^{2}F^{\circ}}$&  14~526.59& & 28~127.85&14   & Hyd\\ 
K~{\sc{i}}&9& 19&[Ar]${\rm 6p}$ &${\rm ^{2}P^{\circ}}$&  16~648.27& & 29~004.90& 6   & Hyd\\ 
K~{\sc{i}}&10& 19&[Ar]${\rm 5d}$ &${\rm ^{2}D}$& 20~721.96& & 30~185.40&10   & Hyd\\ 
K~{\sc{ii}}&1& 19&[Ar] 	      &  ${\rm ^{1}S}$&  & & 0.00 &1 & -- \\    
Ca~{\sc{i}}&1& 20&[Ar]${\rm 4s^2}$& ${\rm ^{1}S}$	&  2027.60&  49~305.95&    0.00 &1& OP \\
Ca~{\sc{i}}&2&20&[Ar]${\rm 4s4p}$  & ${\rm ^{3}P^{\circ}}$&  2936.66&		&15~263.09&9& OP\\
Ca~{\sc{i}}&3& 20&[Ar]${\rm 3d4s}$&${\rm ^{1}D^{\circ}}$& 3641.13&   &    21~849.63& 5  & OP\\ 
Ca~{\sc{ii}}&1& 20&[Ar]${\rm 4s}$ &  ${\rm ^{2}S}$&  & & 0.00 &2& -- \\    
Sc~{\sc{i}}&1&21& [Ar]${\rm 3d4s^2}$  & ${\rm ^{2}D}$ & 1896.81 & 52~922.0& 0.0  & 10  & Hyd\\
Sc~{\sc{ii}}&1&21& [Ar]${\rm 3d4s}$  & ${\rm ^{3}D}$ &  & & 0.0 & 15 & --\\
Ti~{\sc{i}}&1&22& [Ar]${\rm 3d^2 4s^2}$& ${\rm ^{3}F}$ & 1831.05 & 55~010.0& 0.0 & 21   &   Hyd\\
Ti~{\sc{ii}}&1&22& [Ar]${\rm 3d^2 4s}$  & ${\rm ^{4}F}$ &  &        & 0.0 & 28   &   --\\
V~{\sc{i}}&1&23& [Ar]${\rm 3d^3 4s^2}$  & ${\rm ^{4}F}$ & 1861.26 & 54~360.0& 316.484    &30  & Hyd\\
V~{\sc{ii}}&1&23& [Ar]${\rm 3d^4}$  & ${\rm ^{5}D}$ &  & & 0.0 & 25 & --\\
Cr~{\sc{i}}&1&24& [Ar]${\rm 3d^5 4s}$  & ${\rm ^{7}S}$ & 1832.32 &54~575.6  &  0.0   & 7& Hyd\\
Cr~{\sc{ii}}&1&24& [Ar]${\rm 3d^5}$  & ${\rm ^{6}S}$ &  & & 0.0 &6 & --\\
Mn~{\sc{i}}&1&25& [Ar]${\rm 3d^5 4s^2}$  & ${\rm ^{6}S}$ &1667.80  & 59~959.40&  0.0   &6 & Hyd\\
Mn~{\sc{ii}}&1&25& [Ar]${\rm 3d^5 4s}$  & ${\rm ^{7}S}$ &  & & 0.0 &7 & --\\
Fe~{\sc{i}}&1&26&[Ar]${\rm 3d^6 4s^2}$&${\rm ^5D}$ &  1589.04&  63~737.00&    402.96 &25& OP \\
Fe~{\sc{i}}&2&26&[Ar]${\rm 3d^7 (^4F)4s}$ &  ${\rm ^5F}$ &  1789.67&   &   7457.82 &35 &OP\\
Fe~{\sc{i}}&3&26&[Ar]${\rm 3d^7(^4F)4s}$ &  ${\rm ^3F}$ &  *~1873.48  & &   12~408.10 & 21 &OP\\
Fe~{\sc{i}}&4&26&[Ar]${\rm 3d^7(^4P)4s}$ &  ${\rm ^{5}P}$ &  2193.69   & &    17~761.40& 15 &OP\\
Fe~{\sc{i}}&5&26&[Ar]${\rm 3d^6 4s^2}$  &    ${\rm ^{3}P}$ &   2266.85&  & 19~232.20 &9& OP\\
Fe~{\sc{ii}}&1&  26&[Ar]${\rm 3d^6 (^5D)4s}$ & ${\rm ^{6}D}$& & &  0.00 &30 & -- \\
Co~{\sc{i}}&1&27& [Ar]${\rm 3d^7 4s^2}$  & ${\rm ^{4}F}$ & 1616.96 & 63~430.0&792.80 & 28 & Hyd\\
Co~{\sc{ii}}&1&27& [Ar]${\rm 3d^8}$       & ${\rm ^{3}F}$ &  & & 0.0 & 21 & --\\
Ni~{\sc{i}}&1&28& [Ar]${\rm 3d^8 4s^2}$  & ${\rm ^{3}F}$ & 1676.27 & 61~600.0 & 971.80& 21 & Hyd\\
Ni~{\sc{ii}}&1&28& [Ar]${\rm 3d^9}$       & ${\rm ^{2}D}$ &  & & 0.0 & 10 &-\\
Cu~{\sc{i}}&1&29& [Ar]${\rm 3d^10 4s}$   & ${\rm ^{2}S}$ & 1604.69 & 62~317.44 & 0.0    &2& Hyd\\
Cu~{\sc{ii}}&1&29& [Ar]${\rm 3d^10}$      & ${\rm ^{1}S}$ &  &          & 0.0 &1& -- \\
Zn~{\sc{i}}&1&30& [Ar]${\rm 3d^10 4s^2}$  & ${\rm ^{1}S}$ & 1319.80 & 75~769.33& 0.0   &1& Hyd\\
Zn~{\sc{ii}}&1&30& [Ar]${\rm 3d^10 4s}$    & ${\rm ^{2}S}$ &  &          & 0.0        &2& -- \\
\hline
\end{tabular}
\smallskip
$^1$~\citet{John1988}; 
$^2$~\citet{Mihalas1967};
 $^3$~\citet{Koester1985};
 $^4$~hydrogenic treatment;
 $^5$~OPACITY PROJECT and in case of iron the IRON PROJECT.
\end{table}