\begin{table}%t3
\caption{Requisite column densities for unit optical depth in the absorption line centre for the deuterated forms of H$_{3}^{+}$. Spectroscopic data from Ramanlal \& Tennyson (\cite{ramanlal04}). }\label{colcr}
%\begin{center}
{
\begin{tabular}{lccccc}
\hline  \hline
  Species &  Upper level & Lower level  &  $E_{l}$ & Wavelength & $N_{\tau =1}$  \\
          &    & &  (cm$^{-1}$)   &  ($\mu $m)    &  (cm$^{-2}$)  \\
\hline
H$_{2}$D$^{+}$ (para) &  (1, 1, 1)$^a$ &  (0, 0, 0) & 0.0   &  4.162  &  $1.9 \times 10^{14}$  \\
H$_{2}$D$^{+}$ (ortho) & (0, 0, 0) &   (1, 1, 1) & 60.0 &  4.395  &  $6.1 \times 10^{14}$ \\
H$_{2}$D$^{+}$ (ortho) & (2, 0, 2) &   (1, 1, 1) & 60.0 &  4.136  &  $7.1 \times 10^{14}$ \\
H$_{2}$D$^{+}$ (ortho) & (2, 2, 0) &   (1, 1, 1) & 60.0 &  3.985  &  $4.9 \times  10^{14}$ \\
D$_{2}$H$^{+}$ (ortho) & (1, 1, 1) &   (0, 0, 0) & 0.0   &  4.965  &  $4.7 \times 10^{14}$ \\
D$_{2}$H$^{+}$ (ortho) & (1, 0, 1) &   (0, 0, 0) & 0.0   &  4.72   &  $5.5 \times 10^{14}$ \\
D$_{2}$H$^{+}$ (para) &  (1, 1, 0) &  (1, 0, 1)  & 34.9 &  5.02   &  $6.9 \times  10^{14}$ \\
D$_{2}$H$^{+}$ (para) &  (2, 0, 2) &  (1, 0, 1)  & 34.9 &  4.63   &  $7.6 \times 10^{14}$ \\
D$_{3}^{+}$ (ortho) &  (0, 1, 1, 0, 1)$^b$ & (0, 0, 0, 0, 0) & 0.0   &  5.296  &  $2.2 \times 10^{13}$ \\
D$_{3}^{+}$ (meta) & (0, 1, 0, 1, 1)  & (0, 0, 1, 1, 0) & 32.3 &  5.548  &  $1.6 \times 10^{14}$ \\
D$_{3}^{+}$ (meta) & (0, 1, 2, 1, $-$1)  & (0, 0, 1, 1, 0) & 32.3 & 5.198   &  $9.9 \times 10^{13}$ \\
D$_{3}^{+}$ (meta) & (0, 1, 2, 1, 1)  & (0, 0, 1, 1, 0) & 32.3 & 5.166   &  $9.1 \times 10^{13}$ \\
D$_{3}^{+}$ (para) & (0, 1, 1, 0, $-$1)  & (0, 0, 1, 0, 0) & 43.6 & 5.433   &  $4.5 \times 10^{14}$ \\
\hline
\end{tabular}}
\parbox{13cm}{
$^a$ ($J, K_{\rm a}, K_{\rm c}$).   \\
$^b$ ($\nu _{1}, \nu _{2}, J, G, U$). }
%\end{center}
\end{table}