\begin{table}%t4
%\centering
\par
\caption{Initial conditions based  mainly on a grain-surface chemistry model  with an accreting~D/H ratio of~0.3.\label{tab:init}}
\begin{tabular}{lcll}
\hline\hline
Species & Abundance & Isotopomer &Fractionation \\
   & ( relative to H)        &&   \\
\hline
H$_2$O   & 1.0(--5)  & HDO        & 0.33   \\
        &            & D$_2$O     & 0.03   \\
H$_2$CO  &  2.0(--8) & HDCO       & 0.28    \\
        &            & D$_2$CO    & 0.02    \\
CH$_3$OH & 1.0(--7)  & CH$_3$OD   & 0.18    \\
        &            & CH$_2$DOH  & 0.64   \\
        &            & CH$_2$DOD  & 0.11   \\
        &            & CHD$_2$OH  & 0.14   \\
        &            & CHD$_2$OD  & 0.03   \\
        &            & CD$_3$OH   & 0.012  \\
        &            & CD$_3$OD   & 0.0023  \\
H$_2$S   & 1.0(--10) & HDS        & 0.33   \\
         &           & D$_2$S     & 0.03     \\
\hline
\end{tabular}
\label{frac}
\end{table}