\begin{table}%t7
%\centering
\par
\caption{\label{table7}Peak position of bands formed after irradiation of CO:H$_2$S ice mixtures 10:1 (mixture~1) and 1:10 (mixture~2) and of a layered film.}
\small \begin{tabular}{c c c c}
\hline\hline\noalign{\smallskip}
\multicolumn{3}{c}{Wavenumber (cm$^{-1}$)} & Molecule \\
mixture 1 & mixture 2 & layered &  \\
\hline
3707 &      & 3707 & CO$_2$ \\
2486 & 2489 & 2487 & H$_2$S$_2$ \\
     &      & 2399 & C$_3$O$_2$ \\
2345 & 2338 & 2346 & CO$_2$ \\
2281 &      & 2280 & $^{13}$CO$_2$ \\
2258 &      &      &             \\
2247 &      & 2248 & C$_3$O \\
2243 &      & 2242 & C$_3$O$_2$ \\
2229 &      &      &    \\
2214 &      & 2212 & C$_5$O$_2$ \\
2192 &      & 2192 & OCC$^{13}$CO \\
2122 &      & 2122 & C$_7$O$_2$ \\
2070 &      & 2061 & C$_5$O$_{2}$ \\
2043 & 2037 & 2040 & OCS \\
1989 &      & 1989 & C$_2$O \\
1858 &      & 1858 & HCO \\
1519 & 1515 &      & CS$_2$ \\
1327 &      &      & SO$_2$ \\
1149 &      &      & SO$_2$ \\
1044 &      &      & O$_3$ \\
658  &      & 659  & CO$_2$ \\
\hline 
\end{tabular}
\end{table}