\begin{table}%tA.2
\caption{\label{tab:t2}Values of $C^{20}_{ll'{mm'}}$.}
%\centering
\small
\begin{tabular}{c|cccccc}
\hline \hline
mm$'$/\ $ll'$ & 2, 0 & 2, 1 & 2, 2 & 1, 1 & 1, 2 & 0, 2 \\ 
\hline
%&&&&&& \\[-8pt]
2, $-$2  & 0 & 0 & $-\frac{1}{\sqrt{4\pi}}~\frac{12\sqrt{5}}{7}$ & 0 & 0  & 0  \\  
1, $-$1  & 0 & 0 & $-\frac{1}{\sqrt{4\pi}}~\frac{12\sqrt{5}}{7}$ &  $\frac{1}{\sqrt{4\pi}}~\frac{4}{\sqrt{5}}$ &  0 & 0  \\  
0, 0   & $\frac{1}{\sqrt{4\pi}}$ & 0 & $\frac{1}{\sqrt{4\pi}}~\frac{12\sqrt{5}}{7}$ &  $\frac{1}{\sqrt{4\pi}}~\frac{2}{\sqrt{5}}$ &  0 & $\frac{1}{\sqrt{4\pi}}$ \\ 
$-$1, 1 & 0 & 0 & $-\frac{1}{\sqrt{4\pi}}~\frac{12\sqrt{5}}{7}$ &  $\frac{1}{\sqrt{4\pi}}~\frac{4}{\sqrt{5}}$ &  0 & 0  \\  
$-$2, 2 & 0 & 0 & $-\frac{1}{\sqrt{4\pi}}~\frac{12\sqrt{5}}{7}$ & 0  & 0 &  0 \\[4pt]
\hline
\end{tabular}
\end{table}