\begin{table}%t2
\caption{Stopping power values (S) adopted in this work.}\label{stopping}
%\centering
\small
\begin{tabular}{lcc}
\hline
\hline
Mixture & Ion and energy & $S$ \\
        &               & 10$^{-15}$eV cm$^2$ molecule$^{-1}$ \\
\hline
\wat & H$^+$, 200 keV & 22.5 \\
\wat & H$^+$, 1 MeV  & 7.8 \\
\wat:CO~= 10:1 & H$^+$, 200 keV & 250.3 \\
\wat:CO~= 10:1 & H$^+$, 1 MeV & 88.2 \\
\wat:\coo~= 1:1 & He$^+$, 200 keV & 175.5 \\
\wat:\coo~= 5:1 & He$^+$, 200 keV & 445.8 \\
\wat:\coo~= 10:1 & H$^+$, 200 keV & 265.1 \\
\wat:\coo~= 10:1 & H$^+$, 1 MeV & 93.9 \\
\wat:\met~= 1:1 & He$^+$, 30 keV & 67.8 \\
\hline
\end{tabular}
\end{table}