**Table 1:** Energy threshold of reactions induced by positrons.
$\begin{table}\begin{displaymath}\begin{array}[b]{lc} \hline \hline \mbox{Proc... ... H$_{2}^{*}$} & \mbox{12.0} \\ \hline \end{array}\end{displaymath}\end{table}$

	1 Introduction
	2 In-flight processes
	3 Processes after thermalization
	4 Annihilation spectra
	5 Summary and conclusions
	References