\begin{table}%t3
  %\centering

  

  \caption{\label{tab3}Cross sections for the CO, O$_{3}$, CO$_{3}$, and C$_{3}$ molecule \mbox{formation}.}
  %\centering

  \begin{tabular}{l l}
  \hline \hline
  Molecules & $\sigma_{f}~(10^{-13}$ cm$^{2}$)  \\
  \hline
  CO                 & 1.6 \\
  O$_{3}$            & 0.15 \\
  CO$_{3}$           & 0.45 \\
  C$_{3}$            & -- \\
  \hline
  \end{tabular}
\end{table}