\begin{table}%t4
\caption{Line widths (in~keV) for various positron annihilation 
processes.\label{tab:FWHM}}
   $$
\begin{array}[b]{lcccc}
\hline
\hline
\mbox{Process/medium} & 
\mbox{Cold and molecular}& 
\mbox{Warm neutral }& 
\mbox{Warm ionized }& 
\mbox{Hot } \\
& \quad \mbox{($T < 100$ K)} \quad & \quad \mbox{($T \sim  8000$ K)} \quad 
&  \quad \mbox{($T \sim  8000$ K)}  \quad & \quad \mbox{($T \sim  10^6$ 
K)} \quad \\
\hline
\mbox{Charge Exchange with H in-flight} & 5.8 & 5.8 &  -& - \\
\mbox{Charge Exchange with H$_2$ in-flight} & 6.4 & -  &  -& - \\
\mbox{Charge Exchange with He in-flight} & 7.4 & 7.4 & 8.7 & - \\
\mbox{Charge Exchange with H after thermalization} \quad & - & 1.16 & -& - \\
\mbox{Charge Exchange with H$_2$ after thermalization} \quad & -& - & -& - \\
\mbox{Charge Exchange with He after thermalization} \quad & -& 1.22 & 1.22 & - \\
\mbox{Direct Annihilation with H}& 1.56 & 1.56 & -& - \\
\mbox{Direct Annihilation with H$_2$}& 1.71 & - & - & - \\
\mbox{Direct Annihilation with He}& 2.50 & 2.50 & 2.50 & - \\
\mbox{Radiative Combination}& -  & -  & 0.98 & 11 \\
\mbox{Direct Annihilation with electrons}& -& -& 0.98 & 11 \\
\mbox{Positronium from grains}& 1.4 & 1.4 & 1.4 & 1.4 \\
\mbox{Annihilation in grains}& 2.0 & 2.0 & 2.0 & 2.0 \\
  \hline
\end{array}$$
%\vspace*{2mm}
\end{table}