Harpoon mechanism of formation of excimer molecules in an electric-discharge XeCl laser

The harpoon mechanism of formation of XeCl* excimer molecules was identified experimentally and various characteristics were studied when Cl₂–Xe–He mixtures were excited by an electric discharge in the chamber of a standard ÉLI excimer laser. Time dependences of the spontaneous emission of XeCl* molecules and of the gain and absorption coefficients were investigated as functions of the Cl₂ and Xe pressures. The investigation showed that, firstly, the harpoon mechanism of formation of XeCl* molecules predominated over the ion recombination mechanism (at least at the leading edge of the discharge pulse) and its role increased with decreasing input energy. Secondly, there was no additional absorption compared with conventional HCl-based mixtures, except for the absorption due to the presence of Cl₂.