\begin{table}%t1
\caption{\label{tab:initial}The initial abundances.}
%\centerline
 {\begin{tabular}{ll}
\hline
\hline
Species&Abundance$^{a}$\\
       &(relative to the number of hydrogen nuclei)\\
\hline
H       & 0.0\\
H$_{2}$ & 0.5\\
He      & 9.75(--2)\\
O       & 1.80(--4)\\
C$^{+}$ & 7.86(--5)\\   
N       & 2.47(--5)\\
Mg$^{+}$& 1.09(--8)\\
Na$^{+}$& 2.25(--9)\\
Fe$^{+}$& 2.74(--9)\\
S$^{+}$ & 9.14(--8)\\
Cl$^{+}$& 1.00(--9)\\
P$^{+}$ & 2.16(--10)\\
F       & 2.00(--10)\\
Si$^{+}$& 9.74(--9)\\
e$^{-}$ & 7.87(--5)\\
Grains  & 1.33(--12)\\
\hline
\end{tabular}}
\par
\smallskip
$^{a}$ Abundances are given as $a(b) = a \times 10^{b}$.
\par
The initial abundances, most of them were taken from \cite{2001ApJ...552..639A}, the grain abundance was taken from \cite{1992ApJS...82..167H}. For the fluorine abundance we take a fifth of chlorine abundance \citep{1994ApJ...433..729Z}.
\end{table}