\begin{table}%t1
\caption{\label{tbl-1}Infrared band position (cm$^{-1}$) and assignment of pure methylammonium
methylcarbamate (C) at 10~K, pure methylammonium glycinate (G) at 10~K, 
pure methylamine at 10~K and pure methylcarbamic acid.}
%\centerline
 {
\begin{tabular}{lcccc}
\hline
\hline
Vibration & [CH$_{3}$NH$_{3}^{+}$][CH$_{3}$NHCOO$^{-}$] & [CH$_{3}$NH$_{3}^{+}$][NH$_{2}$CH$_{2}$COO$^{-}$] & CH$_{3}$NH$_{2}$ & CH$_{3}$NHCOOH\\
& (C)$^{\footnotesize{1}}$ & (G)$^{\footnotesize{2}}$ & Methylamine$^{\footnotesize{3}}$ & Methylcarbamic acid$^{\footnotesize{4}}$\\
\hline
$\nu$~NH H bonding &  $\cdots$        &  $\cdots$       &   $\cdots$       &    3367 \\
$\nu_{\rm as}$~NH$_{2}$ &     $\cdots$      &       3340 &       3343 & $\cdots$    \\
$\nu$~NH &       3287 &    $\cdots$      &  $\cdots$     &    $\cdots$   \\
$\nu_{\rm s}$~NH$_{2}$ &  $\cdots$  &       3285 &       3282 &  $\cdots$       \\
H bonding &  $\cdots$   &       3210 &       3182 &           \\
 $\nu$~OH &  $\cdots$      & $\cdots$ & $\cdots$  &   3062/2985 \\ 
$\nu_{\rm s}$~NH$_{3}$ CH$_{3}$NH$_{3}^{+}$&       3002 &       3005 &   $\cdots$   & $\cdots$ \\
Combination CH$_{3}$NH$_{3}^{+}$ &       2642 &       2651 & $\cdots$    &  $\cdots$ \\
Combination CH$_{3}$NH$_{3}^{+}$ &       2544 &       2549 &  $\cdots$  &  $\cdots$  \\
 $\nu$~C=O  &  $\cdots$  & $\cdots$  &   $\cdots$  & 1679/1672 \\
$\delta_{\rm as}$~NH$_{3}$ CH$_{3}$NH$_{3}^{+}$&       1652 &       1655 &  $\cdots$  & $\cdots$  \\
$\delta$~NH$_{2}$ &  $\cdots$  &       1635 &       1615 &  $\cdots$  \\
$\nu$~CN + $\delta$~NH &  $\cdots$  &  $\cdots$   &   $\cdots$     & 1574/1533 \\
 $\nu_{\rm as}$~COO$^{-}$ &       1578 &       1565 &    $\cdots$  &  $\cdots$ \\
 $\delta$~NH &       1494 & $\cdots$  & $\cdots$  & $\cdots$  \\
$\delta_{\rm as}$~CH$_{3}$ CH$_{3}$NH$_{3}^{+}$ &       1471 &       1471 & $\cdots$ & $\cdots$ \\
$\delta_{\rm d}$~CH$_{3}$ &  1347 & $\cdots$   &  1478/1455 & 1441/1420 \\
 $\delta$~CH$_{2}$ & $\cdots$  &       1442 & $\cdots$  & $\cdots$ \\
$\nu_{\rm s}$~COO$^{-}$ &       1410 &       1403 &  $\cdots$   &$\cdots$   \\
$\delta$~OH &   $\cdots$  &  $\cdots$   &$\cdots$    &       1396 \\
   tw~NH$_{2}$ & $\cdots$  &       1330 &       1339 & $\cdots$ \\
  tw~CH$_{2}$ & $\cdots$   &       1310 & $\cdots$ & $\cdots$ \\
$\delta$~OH + $\nu$~C--O & $\cdots$ &  $\cdots$  & $\cdots$  & 1315/1263 \\
\hline
\end{tabular}}
\medskip
\par
References. (1) \citep{Waldron53,Cabana62,Castellucci74,Bossa08a}; (2) \citep{Rosado98}; (3) \citep{Bossa08a,Durig68}; (4)  \citep{Bossa08a}.\\
Comments: Vibration mode: stretching ($\nu$), bending ($\delta$) and twisting (tw).\\
Indication: asymmetric (as), symmetric (s) and degenerated (d).
\end{table}