\begin{table}%t2
\caption{\label{TH_tab}Threshold  energy $T_{0}$ and critical kinetic energy~$E_{\rm 0n}$ for H, He and C~ions impacting on a carbon atom.}
%\centering
\small
\begin{tabular}{c c c c}
\hline\hline \noalign{\smallskip}
$T_{0}$  &  $E_{\rm 0n}$(H)  &  $E_{\rm 0n}$(He)  &  $E_{\rm 0n}$(C)  \\
\hline	      
   4.5    &   15.8  &  6.0  &   4.5  \\
   7.5    &   26.4  &  10.  &   7.5  \\
   10.    &   35.2  &  13.  &   10.  \\
   12.    &   42.3  &  16.  &   12.  \\
   15.    &   52.8  &  20.  &   15.  \\
\hline 
\end{tabular}
\tablefoot{$T_{0}$ and $E_{\rm 0n}$ in~eV.}
\end{table}