\begin{table}%t2
   %\centering
\par
    \caption{\label{tab:energies}Energies in Rydbergs for the lowest 29 levels of Ar$^{2+}$.}
    \begin{tabular}{rcccc}
    \hline\hline\noalign{\smallskip}
    Configuration &$^{2S+1}L_J$ &NIST      &Present
    &\%Err \\
                  &             &En. (Ryd) &En. (Ryd) &    \\  
    \hline\noalign{\smallskip} 
        3s$^2$3p$^4$ &($^3$P$_2$) &0.0000 &0.0000 & 0.0  \\			   
        3s$^2$3p$^4$ &($^3$P$_1$) &0.0101 &0.0096 & 5.2  \\			   
        3s$^2$3p$^4$ &($^3$P$_0$) &0.0143 &0.0137 & 4.4  \\			   
        3s$^2$3p$^4$ &($^1$D$_2$) &0.1277 &0.1488 &16.6  \\			   
        3s$^2$3p$^4$ &($^1$S$_0$) &0.3031 &0.2841 & 6.2  \\	       
            3s3p$^5$ &($^3$P$_2$) &1.0370 &1.0023 & 3.3  \\	       
            3s3p$^5$ &($^3$P$_1$) &1.0461 &1.0108 & 3.4  \\		  
            3s3p$^5$ &($^3$P$_0$) &1.0509 &1.0152 & 3.4  \\	       
            3s3p$^5$ &($^1$P$_1$) &1.3124 &1.3028 & 0.7  \\		   
    3p$^3$(4S$^{\circ}$)3d &($^5$D$_1$) &1.3203 &1.3165 & 0.3  \\			
    3p$^3$(4S$^{\circ}$)3d &($^5$D$_3$) &1.3204 &1.3172 & 0.2  \\ 
    3p$^3$(4S$^{\circ}$)3d &($^5$D$_4$) &1.3205 &1.3178 & 0.2  \\ 
    3p$^3$(4S$^{\circ}$)3d &($^3$D$_3$) &1.4299 &1.4536 & 1.7  \\ 
    3p$^3$(4S$^{\circ}$)3d &($^3$D$_2$) &1.4300 &1.4536 & 1.7  \\ 
    3p$^3$(4S$^{\circ}$)3d &($^3$D$_1$) &1.4310 &1.4545 & 1.6  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^1$S$_0$) &1.4749 &1.5274 & 3.6  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^3$F$_2$) &1.4832 &1.5015 & 1.2  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^3$F$_3$) &1.4861 &1.5047 & 1.3  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^3$F$_4$) &1.4897 &1.5088 & 1.3  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^3$G$_3$) &1.5683 &1.5908 & 1.4  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^3$G$_4$) &1.5686 &1.5915 & 1.5  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^3$G$_5$) &1.5691 &1.5925 & 1.5  \\ 
    3p$^3$(4S$^{\circ}$)4s &($^5$S$_2$) &1.5891 &1.6067 & 1.1  \\ 
    3p$^3$(2D$^{\circ}$)3d &($^1$G$_4$) &1.6008 &1.6339 & 2.1  \\ 
    3p$^3$(2P$^{\circ}$)3d &($^1$D$_2$) &1.6360 &1.6380 & 0.1  \\ 
    3p$^3$(4S$^{\circ}$)4s &($^3$S$_1$) &1.6465 &1.6833 & 2.2  \\ 
    3p$^3$(2P$^{\circ}$)3d &($^3$F$_4$) &1.6986 &1.7044 & 0.3  \\ 
    3p$^3$(2P$^{\circ}$)3d &($^3$F$_3$) &1.7010 &1.7064 & 0.3  \\ 
    3p$^3$(2P$^{\circ}$)3d &($^3$F$_2$) &1.7032 &1.7084 & 0.3  \\ 
    \hline
    \end{tabular}
   \end{table}