\begin{table}%tA.1
\small\caption{Molecular parameters used to estimate $N_{\rm tot}$.}\label{tab:q_func}
%\centerline
{\begin{tabular}{lcc}
\hline\hline\noalign{\smallskip}
 Transition &  $S\mu^2_{g}$$^a$       & $Q(15)$$^b$  \\  
  &   D                                &                \\    
\hline
 \DAMM\ 1$_{11}$--1$_{01}$  (para)  &    11.9                            & 47.8$^c$   \\
 \DDAMM\ 1$_{10}$--1$_{01}$ (ortho) &    0.722                           & 50.2$^d$ \\
 \htcn\  $J=1$--0, $F=2$--1         &    14.84                           & 22.8$^e$ \\
 \hcfn\  $J=1$--0                   &    8.909                           & 7.6$^e$ \\
 \CO\    $J=1$--0                   &    0.012                           &  6.1$^e$ \\
 \CO\    $J=2$--1                   &    0.024                           & 6.1$^e$ \\ 
 \hline
\end{tabular}}
\smallskip
$^a$~$S$ is the line strength and $\mu_{g}$  is the dipole moment along the molecular $g$-axis. $^b$~the partition function corresponding to a temperature of 15~K, the typical temperature of the sources in the present sample.  $^c$~the partition function obtained by the summation over the contribution of the different energy levels from $J=0$ to $J=2$. $^d$~the partition function based on data from the CDMS catalog \citep{mueller2005:cdms}. $^e$~the partition function based on data from the JPL catalog \citep{pickett1998:jpl}.
\end{table}