\begin{table}%t2
\caption{\label{ACbands}Infrared absorption bands and assignments of the products
 formed from a binary NH$_{3}$:CO$_{2}$=1:1.}
\par
%\centerline
 {
\begin{tabular}{lcc}
\hline\hline
\multicolumn{1}{c}{Assignment}&\multicolumn{1}{c}{Wavenumbers
}&\multicolumn{1}{c}{Band Strength}\\
\multicolumn{1}{c}{}&\multicolumn{1}{c}{(cm$^{-1}$)}&\multicolumn{1}{c}{(cm~molecule$^{-1}$)}\\\hline
$\nu$~(NH$_{2}$)  NH$_{2}$COOH  dimer & 3462 & \\
$\nu$~(NH$_{2}$)  [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] &  \\
$\nu$~(NH$_{2}$)  [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] & 3325& \\
$\nu$~(OH) NH$_{2}$COOH dimer& (broad) 3140 & \\
$\nu$~(C=O)  NH$_{2}$COOH dimer& 1691& $5\times10^{-18}$ \\
$\delta$~(NH$_{2}$)  [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$]& 1623 & $2\times10^{-18}$\\
$\nu_{\rm as}$~(COO$^{-}$)   [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] & 1553 & $2\times10^{-17}$\\
$\delta$~(NH$_{4}$$^{+}$)  [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] & 1495 &  $3\times10^{-18}$ \\
NH$_{2}$COOH dimer& 1451 & $2\times10^{-18}$\\
$\nu_{\rm s}$~(COO$^{-}$)   [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] & 1393 & $8\times10^{-18}$\\
NH$_{2}$COOH dimer& 1320 &$2\times10^{-18}$ \\
$\nu$~(CN)   [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$]& 1117 & $4\times10^{-18}$\\
$\rho$~(NH$_{2}$)   [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] & 1037 & $2\times10^{-19}$\\
$\delta_{\rm oop}$~(OCN)   [NH$_{2}$COO$^{-}$][NH$_{4}$$^{+}$] & 829 & $6\times10^{-19}$\\
$\delta$~(COO$^{-}$)   [NH$_{2}$COO$^{-}$][NH$_{4}^{+}$]  & 674 & $4\times10^{-19}$\\
\hline
\end{tabular}}
\medskip
\par
Vibration mode: stretching ($\nu$), bending ($\delta$), rocking ($\rho$), torsion ($\tau$).\\
Indication:  asymmetric (as), symmetric (s) and out-of-plane (oop).
\end{table}