New possible laser media in the UV and XUY in high current heavy ion beam induced plasmas

Mixtures of rare gases with alkali-metal vapour were excited by a high power argon ion beam in a windowless gas target system. Narrow emission continua were observed in the vacuum ultraviolet region between 60 and 200 nm. The observed emission was assigned to the decay of a new class of excited ionic molecules Rg⁺ A formed by the combination of a rare gas ion Rg⁺ with an alkali atom A. These excimer-like ions are of great interest for possible short-wavelength lasers, because the ground state consisting of a rare gas atom and an alkali ion is only weakly bound. The observed decay energies and fine structure splittings agree well with the prediction of calculations. A summary of previous results is presented.Supported by the German Government Department for Research and Technology (BMFT), Bonn, Germany.