\begin{table}%t2
%\centering
\par
\caption{\label{pol_fit}Fit coefficients for the dissociative ionization and double
ionization cross sections of H$_2$ by electron impact.}
\begin{tabular}{lrr}
\hline\hline
$n$  & $a_n$ (diss.~ion) & $a_n$ (doub.~ion)  \\
\hline
0    & $-53.23133$ & $-125.8689$ \\
1    & $ 96.57789$ & $ 172.0709$ \\
2    & $-67.57069$ & $-108.8777$ \\
3    & $ 23.32707$ & $ 34.18291$ \\
4    & $-4.004618$ & $-5.358045$ \\
5    & $ 0.272652$ & $ 0.335476$ \\
\hline
\end{tabular}
\end{table}