\begin{table}%t1
%\centering
\par
\caption{Fitting formulae for momentum transfer coefficients as a function
of the gas temperature $T$ (in K) and $\theta\equiv\log (T/\rm{K})$ for $v_{\rm d}=0$.}\label{rates_vd0}
\begin{tabular}{ll}
\hline\hline
Species $s,s^\prime$ &  $\langle\sigma v\rangle_{ss^\prime}$ \\
        &   ($10^{-9}$~cm$^3$~s$^{-1}$)         \\
\hline\noalign{\smallskip}
HCO$^+$, H$_2$  & $T^{1/2}(1.476-1.409\theta+0.555\theta^2-0.0775\theta^3)$ \\
H$_3^+$, H$_2$  & $2.693-1.238\theta+0.664\theta^2-0.089\theta^3$ \\
H$^+$, H$_2$    & $1.003+0.050\theta+0.136\theta^2-0.014\theta^3$ \\
e, H$_2$      & $T^{1/2}(0.535+0.203\theta-0.163\theta^2+0.050\theta^3)$ \\
%\hline
C$^+$, H    & $1.983+0.425\theta-0.431\theta^2+0.114\theta^3$  \\
H$^+$, H    & $0.649 T^{0.375}$ (GKS) \\
e, H      & $T^{1/2}(2.841+0.093\theta+0.245\theta^2-0.089\theta^3)$  \\
%\hline
H$^+$, He   & $1.424+7.438\times 10^{-6}T-6.734\times 10^{-9}T^2$ \\
e, He     & $0.428 T^{1/2}$ \\
\hline
\end{tabular}
\end{table}