\begin{table}%t4
%%\centering
\par
\caption{\label{tab:newspec}Assignment of infrared absorption features produced by the radiolysis of the H$_2$O:NH$_3$:CO ice (1:0.6:0.4) by 46~MeV~Ni ions at 13~K and after warming to 300~K.} 
%\centerline
 {
 \small \begin{tabular}{ l l l l r }
\hline \hline
Frequency  & Wavelength & Temp.  & Molecule   & Notes \\
(cm$^{-1}$)& ($\mu$m) & (K)       &   &       \\
\hline
2233   & 4.48 & 13       & N$_2$O    & [1,2]  \\
2218--2200      & 4.51-4.54 & 300 &  nitriles$^\dag$   & [8]  \\
2168           & 4.61 & 13, 300  & OCN$^-$  & [1,3,4,7] \\
2147           & 4.66 & 300      & aliph. isocyanide$^\dag$        & [8] \\
$\sim$2112    & 4.73 & 300      & NCO$_2^\dag$                    & [2] \\
1725           & 5.80 & 300    & ester$^\dag$                      & [5]  \\
1683           & 5.94 & 300    & amides$^\dag$                     & [5]  \\
1652           & 6.05 & 300    & asym-N$_2$O$_3^\dag$              & [2]  \\
1637           & 6.11 & 13     & ?                                 &      \\
1593           & 6.28 & 300    & NH$_3^+$CH$_2$COO$^{-\dag}$       & [6]  \\
1558           & 6.42 & 300    & ?                                 &      \\
1533           & 6.52 & 300    & ?                                 &       \\
1506           & 6.64 & 300    & NH$_3^+$CH$_2$COO$^{-\dag}$       &  [6]  \\
$\sim$1490     & 6.71 & 13     & NH$_4^+$                          & [1,3,7] \\
1474           & 6.78 & 13     & NO$_3^\dag$                           & [2]  \\
1440           & 6.94 & 13     & NH$_3^+$CH$_2$COO$^{-\dag}$       & [6]  \\
1415           & 7.07 & 300    & NH$_3^+$CH$_2$COO$^{-\dag}$       & [6]  \\
$\sim$1370    & 7.30 & 13, 300 & HMT$^\dag$  & [5]  \\
&      &         & HCOO$^{-}$  & [5,9]  \\
$\sim$1338     & 7.47 & 13, 300 & NH$_3^+$CH$_2$COO$^{-\dag}$      & [6]  \\
&      &         & NH$_2$CH$_2$COO$^{-\dag}$              & [6]  \\
               &      &         & HCOO$^-$                         & [9]  \\
1305           & 7.66 & 13      & N$_2$O$_3^\dag$; N$_2$O$_4^\dag$ & [2] \\
1283           & 7.80 & 300     & N$_2$O$^\dag$                    & [2] \\
\hline 
\end{tabular}}
\medskip
$^\dag$Tentative assignment. [1] Proton bombardment of several ices (Hudson et~al. \cite{Hudson2001}); [2] Electron bombardment of N$_2$:CO$_2$ (Jamieson et~al. \cite{Jamieson2005}); [3] Hudson \& Moore (\cite{Hudson2000}; [4] van~Broekhuizen et~al. \cite{van2005}; [5] UV~photolysis of H$_2$O:NH$_3$:CH$_3$OH:CO:CO$_2$ ice (Munoz Caro \& Shutte \cite{Munoz2003}); [6] electron bombardment of CH$_3$NH$_2$:CO$_2$ ice (Holtom et~al. \cite{Holtom2005}); [7]~UV photolysis of ammonia-containing ices (Demyk et~al. \cite{Demyk1998}); [8]~UV photolysis of N$_2$:CH$_4$ ices at various pressures (Imanaka et~al. \cite{Imanaka2004}); [9]~proton bombardment of H$_2$O:NH$_3$:CO ice (Hudson \& Moore \cite{Hudson2001}).
\end{table}