Soft-X-ray spectra of highly charged Au ions in an electron-beam ion trap

Systematic variation of the electron-beam energy in an electron-beam ion trap has been employed to produce soft-X-ray spectra (20 to 60 ?) of Au with well-defined maximum charge states ranging from Br- to Co-like ions. Guided by large-scale relativistic atomic structure calculations, the strongest Dn = 0 (n = 4 to nʹ = 4) transitions in Rb- to Cu-like ions (Au42+ - Au50+) have been identified.