Electron liberation from negative ions as a means of laser preionization

An analysis is made of the possible methods of liberation of electrons from atomic negative halide ions in the context of providing sufficient preionization for discharge-pumped rare-gas-halide excimer lasers. Some previous treatments of collisional detachment are shown to be in error by several orders of magnitude. Ion and electron impact detachment of electrons is found to produce a negligible preionization electron number density. Photodetachment is shown to be the dominant electron liberation mechanism, and to be capable of producing electron densities adequate for preionization of the excimer laser discharge.