Rate predictions for two-photon spectroscopy of highly charged ions through laser-induced recombination

Sub-Doppler two-photon spectroscopy of Rydberg states in combination with l aser-induced two-step recombination of highly charged ions and electrons is investigated. From a rate equation model signal strengths and widths are e stimated to study the feasibility of an experiment with helium-like C4+ ion s. The calculations yield measurable signal strengths for the transitions 1 6G --> 8D, 16H --> 8F, 16D --> 8D and 16F --> 8F at reasonable laser intens ities. The estimated linewidths of similar to 0.02 meV permit to resolve th e magnetic fine structure.