\begin{table}%T2
%\centering
\par
\caption{Diagnostic spectral parameters of the 10 and 20~$\mu$m
bands of amorphous magnesium silicates based on calculations of
the absorption cross section per unit volume $C/\langle{V}\rangle$ (in cm$^{-1}$) for small
spheres (Sph.) and a continuous distribution of ellipsoids (CDE)
for particles in the Rayleigh limit. $\lambda$ and $A$ represent
the peak position in~$\mu$m and the absorption cross section per unit volume $C/\langle{V}\rangle$
in cm$^{-1}$, respectively. $W$~stands for the FWHM of the bands.
The band ratio has been calculated by dividing the intensity of
the 20~$\mu$m band by the intensity of the 10~$\mu$m band.}
\label{qda} {\footnotesize
\begin{tabular}{c|cccccc|cccccc|cc}
\hline\hline
      &\multicolumn{6}{c|}{10~$\mu$m}&\multicolumn{6}{c|}{20~$\mu$m}&\multicolumn{2}{c}{band ratio}\\
Comp. &\multicolumn{2}{c}{$\lambda_{10}$
[$\mu$m]}&\multicolumn{2}{c}{$A_{10}$
[cm$^{-1}$]}&\multicolumn{2}{c|}{$W_{10}$ [$\mu$m]}&
\multicolumn{2}{c}{$\lambda_{20}$
[$\mu$m]}&\multicolumn{2}{c}{$A_{20}$
[cm$^{-1}$]}&\multicolumn{2}{c|}{$W_{20}$ [$\mu$m]}&
\multicolumn{2}{c}{$A_{20}/A_{10}$}\\
                     & Sph. & CDE & Sph. & CDE & Sph. & CDE & Sph. & CDE  & Sph.& CDE & Sph. & CDE & Sph. & CDE \\
\hline Mg$_{0.7}$SiO$_{2.7}$& 9.15 &9.20 & 6945 & 7043& 1.41 &1.56
&20.21 &20.86 & 3413& 3825& 5.61 & 5.68& 0.49 & 0.54 \\ MgSiO$_3$
& 9.26 &9.37 & 6165 & 6642& 1.88 &2.10 &19.41 &20.22 & 2520& 3023&
8.53 & 10.0& 0.41 & 0.46 \\ Mg$_{1.5}$SiO$_{3.5}$& 9.62 &9.74 &
6725 & 6992& 1.99 &2.41 &18.11 &18.70 & 3533& 4020& 9.91 & 13.3&
0.52 & 0.57 \\ Mg$_2$SiO$_4$        & 9.80 &9.91 & 6923 & 7395&
2.05 &2.43 &17.42 &17.90 & 3165& 3698& 10.0 & 13.0& 0.47 & 0.50 \\
Mg$_{2.4}$SiO$_{4.4}$&10.07 &10.2 & 4778 & 5198& 2.66 &2.80 &17.11
&17.76 & 3925& 4395& 9.83 & 13.1& 0.82 & 0.84 \\ \hline
\end{tabular}}
\end{table}