SPECTRA OF AG-I ISOELECTRONIC SEQUENCE OBSERVED FROM ER21+ TO AU32+

Spectra of highly ionized Er, Yb, Hf, W, Pt, and Au were observed with the TEXT tokamak at the University of Texas at Austin. These metals w ere injected into the tokamak plasma by laser ablation of thin-film ta rgets. Spectra were photographed with a 2.2-m grazing-incidence spectr ograph in the range 40-300 angstrom. Three strong doublets of the Ag I isoelectronic sequence were identified: 4d(10)4f-4d(9)4f(1P)4f2b, 2F and 2G. Interpolated and extrapolated wavelengths in this sequence wer e derived from plots of the difference between observed and calculated values for the transition energies. The correspondence of the W wavel engths with previously reported tokamak spectra is shown.