\begin{table}%t1
\par
\caption{\label{tab:freac}Fractionation reactions added to the list given in Roberts \& Millar (\cite{Roberts2000a}). The forward rate is $k_{\rm f}$; the reverse rate, $k_{\rm r}$, is given by~$k_{\rm f}$~e$^{-\gamma/{\rm T}}$. }
%\centerline
{
\begin{tabular}{lllllc}
\hline\hline
Reaction && &  $k_{\rm f}$   & $\gamma$ & Ref. \\
     && & (cm$^3$~s$^{-1}$) & (K) & \\
\hline
H$_3^+$  +  ~D$_2$ & $\rightleftharpoons$ &~H$_2$D$^+$ +~HD   &3.5($-$10) & 63 & 1 \\
H$_3^+$   + ~D$_2$ & $\rightleftharpoons$ &~HD$_2^+$  +~H$_2$ & 1.1($-$9) &  251& 1 \\
H$_2$D$^+$ +  ~HD  & $\rightleftharpoons$ &~HD$_2^+$  +~H$_2$ & 8.1($-$10) &  187& 1 \\
H$_2$D$^+$  + ~D$_2$ & $\rightleftharpoons$ &~HD$_2^+$  +~HD  &7.0($-$10) & 107& 1 \\
H$_2$D$^+$   +~D$_2$  & $\rightleftharpoons$ &~D$_3^+$ + ~H$_2$ & 7.0($-$10) &  341& 1 \\
HD$_2^+$   +~HD  & $\rightleftharpoons$ & ~D$_3^+$ +~H$_2$ & 6.4($-$10) & 234& 1 \\
HD$_2^+$   +~D$_2$ & $\rightleftharpoons$ & ~D$_3^+$ +~HD &  8.7($-$10) & 159 & 1 \\
CH$_2$D$^+$ +~HD & $\rightleftharpoons$ & CHD$_2^+$ +~H$_2$ &1.6($-$9)&  370 & 2 \\
CHD$_2^+$ +~HD  & $\rightleftharpoons$ & CD$_3^+$ +~H$_2$  &1.5($-$9)&  370 & 2 \\ 
CH$_3^+$ +~D$_2$ & $\rightleftharpoons$ & CH$_2$D$^+$ +~HD & 4.4($-$10) & 400 & 2 \\
                 & $\rightleftharpoons$ & CHD$_2^+$ +~H$_2$ & 6.6($-$10) & 400 & 2 \\
CH$_2$D$^+$ +~D$_2$  & $\rightleftharpoons$ & CHD$_2^+$ +~HD & 1.2($-$9) & 400 & 2 \\ 
H$_2$D$^+$ +~D & $\rightleftharpoons$ &~HD$_2^+$ +~H & 2.0($-$9) & 550 & 3 \\
HD$_2^+$ +~D & $\rightleftharpoons$ &~D$_3^+$ +~H & 2.0($-$9) & 655 & 3 \\
\hline
\end{tabular}}
\smallskip
Note: $a(-b)$ stands for $a\times10^{-b}$. \\
Refs.: 1. Giles et~al.~(\cite{Giles1992}); 2. Smith et~al.~(\cite{Smith1982a},b); 3. Walmsley et~al.~(\cite{Walmsley2004}).
\end{table}