\begin{table}%T1
%%\centering
\par
\caption{Ion model key.
AST1--AST3: present work ({\sc autostructure}).
HFR1--HFR3: Present work ({\sc hfr}).
HFR4: {\sc hfr} calculation by Jacobs et~al. (\cite{jac89}).
BPR1: Present work ({\sc bprm}).
COR: Cornille data set from Kato et~al. (\cite{kat97}).
SAF: Safronova data set from Kato et~al. (\cite{kat97}) and Safronova \& Shlyaptseva (\cite{saf96}).
MCDF: Multiconfiguration Dirac--Fock calculation by Chen (\cite{chen86}).
}
\label{table1}
\begin{small}
\begin{tabular}{lllllllllllll}
\hline\hline
Feature& AST1& AST2& AST3& HFR1& HFR2& HFR3& HFR4& BPR1& COR& SAF& MCDF\\
\hline
Orthogonal orbital basis   & Yes& Yes& Yes& Yes & No & No & No&Yes& Yes& Yes &Yes \\
CI from $n>2$ complexes    & No & No & Yes& No  & No & Yes& No&No & No & Yes &Yes \\
Breit interaction          & No & Yes& Yes& Yes & Yes& Yes& Yes&No & No & Yes &Yes \\
QED effects                & No & No & No & No  & No & No & No&No & No & Yes &Yes \\
Semi-empirical corrections & No & No & Yes& No  & No & Yes& No&No & No & No  & No \\
\hline
\end{tabular}
\end{small}
\end{table}