\begin{table}%t2
\caption{Complex refractive indices ($m=n+{\rm i}~k$) at a wavelength~$\lambda$ for a~mixture of carbonaceous materials, magnesium-rich silicate, and iron-bearing sulfide.}\label{tbl2}
%\centerline
{
\begin{tabular}{lll}
\hline
\hline
${{f}_{{\rm or}}}^{{a}}$ &$m~{\rm at}~\lambda=450~{\rm nm}$   &$m~{\rm at}~\lambda=600~{\rm nm}$ \\
\hline
0.00 &$1.85+{\rm i}~6.07\times{10}^{-1}$&$1.98+{\rm i}~6.43\times{10}^{-1}$\\
0.05 &$1.85+{\rm i}~5.92\times{10}^{-1}$&$1.98+{\rm i}~6.26\times{10}^{-1}$\\
0.10 &$1.84+{\rm i}~5.76\times{10}^{-1}$&$1.97+{\rm i}~6.08\times{10}^{-1}$\\
0.15 &$1.84+{\rm i}~5.61\times{10}^{-1}$&$1.97+{\rm i}~5.91\times{10}^{-1}$\\
0.20 &$1.84+{\rm i}~5.45\times{10}^{-1}$&$1.96+{\rm i}~5.73\times{10}^{-1}$\\
0.25 &$1.84+{\rm i}~5.30\times{10}^{-1}$&$1.96+{\rm i}~5.56\times{10}^{-1}$\\
0.30 &$1.84+{\rm i}~5.14\times{10}^{-1}$&$1.95+{\rm i}~5.38\times{10}^{-1}$\\
\hline
\end{tabular}}
\medskip
$^{{a}}$ The volume fraction of organic refractory occupying carbonaceous materials is given as~${f}_{{\rm or}}$ and thus that of amorphous carbon is $1-{f}_{{\rm or}}$.
\end{table}