\begin{table}%t7
%%\centering
\par
\caption{Column densities of the asymmetric
aliphatic peaks in the region
2800$-$3000~cm$^{-1}$ present in the IDPs spectra after the HF treatment, and
of the IRS 7~source of the Galactic Center. The estimated error of these values, due
to spectral noise and the quality of the Gaussian fit, is
$\sim$10\%.\label{aliphatic}}
\begin{tabular}{cccccc}
        \hline\hline
        IDP & area [CH$_{2}$]asym    &  $N$[CH$_{2}$] &  area [CH$_{3}$]asym  & $N$[CH$_{3}$] & $N$[CH$_{2}$]/$N$[CH$_{3}$]  \\
&   $\sim$2922~cm$^{-1}$ & (groups/cm$^{2}$)&  $\sim$2958~cm$^{-1}$ & (groups/cm$^{2}$)& \\
        \hline
L2036-E19 &  --  &  --  &   -- &   --  &  --   \\
L2021-K3  & 0.039 & $1.1 \times 10^{16}$ &   0.014 &   $2.6 \times 10^{15}$ & 4.2 \\
L2021-K2 &  0.059 & $1.6 \times 10^{16}$ &   0.016 &   $2.9 \times 10^{15}$  &  5.5   \\
L2011-F2 &  0.036 & $1.0 \times 10^{16}$ &   0.017 &   $3.2 \times 10^{15}$ &  3.1   \\
W7116B-N &  0.071 & $1.9 \times 10^{16}$ &   0.037 &   $6.8 \times 10^{15}$ &  2.8   \\
W7116B-Y &  0.121 & $3.3 \times 10^{16}$ &   0.050 &   $9.2 \times 10^{15}$ &  3.6   \\
W7116B-U &  0.062 & $1.7 \times 10^{16}$ &   0.033 &   $6.1 \times 10^{15}$ & 2.8   \\
Average &            &                 &           &          &   3.7  \\
\par
	\hline
	IRS 7 &  9.64  &  $2.6 \times 10^{18}$ &   6.68 &   $1.2 \times 10^{18}$ &  2.2 \\
        \hline
    	\end{tabular}
	\end{table}