RH-I ISOELECTRONIC SEQUENCE OBSERVED FROM ER(23+) TO PT(33+)

The TEXT tokamak was used to obtain spectra of highly ionized Er, Yb, Hf, W, and Pt. Injection of these elements into the plasma was achieve d by laser ablation of thin films of metal deposited on glass slides a nd mounted at the inner wall of the vessel. The spectra were photograp hed with a 2.2-m grazing-incidence spectrograph set at a grazing angle of 4-degrees. These spectra occur in a very small wavelength interval , for example, approximately 2 angstrom at 50 angstrom in W In this sp ectral range we previously classified lines of the Ag and Pd isoelectr onic sequences. We have now classified lines of the Rh isoelectronic s equence 4d9-4d84f which accounts for the remaining strong lines in thi s dense but well-resolved group. No lines of this array have previousl y been identified. They were classified by comparison of observed and calculated transition energies along the isoelectronic sequence.