\begin{table}%tA.1
\caption{Rate coefficients adopted in our chemical model for the reactions relating to the meta, ortho and para forms of multiply-deuterated species. The parameters~$\alpha$, $\beta$, and~$\gamma$ define the rate coefficients~$k$~(cm$^3$~s$^{-1}$) at temperature~$T$ through the relation $k$~= {{\it \~J}}$(a_{\rm g}, T)\gamma (T/300)^{\alpha } {\rm exp}(-\beta /T)$; {{\it \~J}} allows for Coulomb focusing in reactions of positive ions and negatively charged grains (Draine \& Sutin 1987, Eq.~(3.4)); $a_{\rm g}$~= 0.1~\mic\ is adopted in the table. The rates~(s$^{-1}$) of reactions induced directly by cosmic rays~(crp) are given by~$\gamma \zeta$, where~$\zeta$ is the rate of cosmic ray ionization of~H$_2$. "g'' denotes "grain'', "m'', "o'' and~"p'' denote "meta'', "ortho'' and~"para'', respectively. Key reactions are in bold face. Numbers in parentheses are powers of~10. (The present table is complementary to that in Appendix~A of Walmsley et~al. \cite{walmsley04}.)}\label{tabA.1}
%\centering
\par
\begin{tabular}{lccc}
\hline \hline
 Reaction & $\gamma$ & $\alpha$ & $\beta$\\
\hline
 D         +  D      $\rightarrow$ D$_2$(p)                    & 0.33&&\\
 D         +  D      $\rightarrow$ D$_2$(o)                    & 0.67&&\\
\par
 D$_2$(p)  +  crp    $\rightarrow$ D$^+$  +  D    +  e$^-$    & 0.04&&\\
 D$_2$(p)  +  crp    $\rightarrow$ D      +  D                & 1.50&&\\
 D$_2$(p)  +  crp    $\rightarrow$ D$_2$$^+$(p)   +  e$^-$    & 0.96&&\\
 D$_2$(o)  +  crp    $\rightarrow$ D$^+$  +  D    +  e$^-$    & 0.04&&\\
 D$_2$(o)  +  crp    $\rightarrow$ D      +  D                & 1.50&&\\
 D$_2$(o)  +  crp    $\rightarrow$ D$_2$$^+$(o)   +  e$^-$    & 0.96&&\\
\par
 H$^+$  +  D$_2$(p)  $\rightarrow$  D$^+$  +  HD                   & 2.10($-$09) & 0.00 &   405.0\\
 H$^+$  +  D$_2$(o)  $\rightarrow$  D$^+$  +  HD                   & 2.10($-$09) & 0.00 &   491.0\\
 D$^+$  +  HD  $\rightarrow$  H$^+$  +  D$_2$(p)                   & 0.50($-$09) & 0.00 &     0.0\\
 D$^+$  +  HD  $\rightarrow$  H$^+$  +  D$_2$(o)                   & 0.50($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(p)  +  H$_2$(p)  $\rightarrow$  H$_2$D$^+$(p)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(o)  +  H$_2$(p)  $\rightarrow$  H$_2$D$^+$(p)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(p)  +  H$_2$(o)  $\rightarrow$  H$_2$D$^+$(o)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(o)  +  H$_2$(o)  $\rightarrow$  H$_2$D$^+$(o)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(p)  +  H$_2$(p)  $\rightarrow$  D$_2$H$^+$(p)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(o)  +  H$_2$(p)  $\rightarrow$  D$_2$H$^+$(o)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(p)  +  H$_2$(o)  $\rightarrow$  D$_2$H$^+$(p)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 D$_2$$^+$(o)  +  H$_2$(o)  $\rightarrow$  D$_2$H$^+$(o)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(p)  +  D$_2$(p)  $\rightarrow$  H$_2$D$^+$(p)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(p)  +  D$_2$(o)  $\rightarrow$  H$_2$D$^+$(p)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(o)  +  D$_2$(p)  $\rightarrow$  H$_2$D$^+$(o)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(o)  +  D$_2$(o)  $\rightarrow$  H$_2$D$^+$(o)  +  D     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(p)  +  D$_2$(p)  $\rightarrow$  D$_2$H$^+$(p)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(p)  +  D$_2$(o)  $\rightarrow$  D$_2$H$^+$(o)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(o)  +  D$_2$(p)  $\rightarrow$  D$_2$H$^+$(p)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 H$_2$$^+$(o)  +  D$_2$(o)  $\rightarrow$  D$_2$H$^+$(o)  +  H     & 1.05($-$09) & 0.00 &     0.0\\
 HD$^+$  +  HD  $\rightarrow$  H$_2$D$^+$(p)  +  D                 & 5.25($-$10) & 0.00 &     0.0\\
 HD$^+$  +  HD  $\rightarrow$  H$_2$D$^+$(o)  +  D                 & 5.25($-$10) & 0.00 &     0.0\\
 HD$^+$  +  HD  $\rightarrow$  D$_2$H$^+$(p)  +  H
& 5.25($-$10) & 0.00 &     0.0\\
 HD$^+$  +  HD  $\rightarrow$  D$_2$H$^+$(o)  +  H                 & 5.25($-$10) & 0.00 &     0.0\\
 H$_2$D$^+$(p)  +  D  $\rightarrow$  D$_2$H$^+$(p)  +  H           & 0.50($-$09) & 0.00 &     0.0\\
 H$_2$D$^+$(p)  +  D  $\rightarrow$  D$_2$H$^+$(o)  +  H           & 0.50($-$09) & 0.00 &     0.0\\
 H$_2$D$^+$(o)  +  D  $\rightarrow$  D$_2$H$^+$(p)  +  H           & 0.50($-$09) & 0.00 &     0.0\\
 H$_2$D$^+$(o)  +  D  $\rightarrow$  D$_2$H$^+$(o)  +  H           & 0.50($-$09) & 0.00 &     0.0\\
 D$_2$H$^+$(p)  +  H  $\rightarrow$  H$_2$D$^+$(p)  +  D           & 1.00($-$09) & 0.00 &     0.0\\
 D$_2$H$^+$(o)  +  H  $\rightarrow$  H$_2$D$^+$(p)  +  D           & 1.00($-$09) & 0.00 &   600.0\\
 D$_2$H$^+$(p)  +  H  $\rightarrow$  H$_2$D$^+$(o)  +  D           & 1.00($-$09) & 0.00 &   463.3\\
 D$_2$H$^+$(o)  +  H  $\rightarrow$  H$_2$D$^+$(o)  +  D           & 1.00($-$09) & 0.00 &   513.5\\
 H$_3$$^+$(o)  +  D$_2$(p)  $\rightarrow$  H$_2$D$^+$(o)  +  HD    & 3.50($-$10) & 0.00 &     0.0\\
 H$_3$$^+$(o)  +  D$_2$(o)  $\rightarrow$  H$_2$D$^+$(o)  +  HD    & 3.50($-$10) & 0.00 &     0.0\\
 H$_3$$^+$(o)  +  D$_2$(p)  $\rightarrow$  D$_2$H$^+$(p)  +  H$_2$(o)   & 3.50($-$10) & 0.00 &     0.0\\
 H$_3$$^+$(o)  +  D$_2$(o)  $\rightarrow$  D$_2$H$^+$(o)  +  H$_2$(o)   & 3.50($-$10) & 0.00 &     0.0\\
 H$_3$$^+$(p)  +  D$_2$(p)  $\rightarrow$  D$_2$H$^+$(p)  +  H$_2$(p)   & 2.33($-$10) & 0.00 &     0.0\\
 H$_3$$^+$(p)  +  D$_2$(o)  $\rightarrow$  D$_2$H$^+$(o)  +  H$_2$(p)   & 2.33($-$10) & 0.00 &     0.0\\
\hline
\end{tabular}
\end{table}