R R Kildiyarova

EUV spectra of Gd and Tb ions excited in laser-produced and vacuum spark plasmas

Extreme UV spectra of the gadolinium and terbium ions excited in the laser-produced plasma and vacuum spark sources were recorded in the 40–120 A region and investigated on the basis of the Hartree–Fock calculations using Cowan code. The intense peaks in the 65–75 A region of the vacuum spark spectra were interpreted as a manifold of the 4d104fm–4d94fm+1 transitions in the ions with a partially filled 4f shell. The drastic narrowing of these peaks was observed in the spectra of the laser-produced plasma. It was explained by a change of the 4d104fm–4d94fm+1 (m>2) transition arrays mostly contributing to the intensity of the peaks in the vacuum spark spectra for the 4–4 transitions in the simplest spectra of the 4p64dk (k=8–10) and 4d104fm (m=1–2) ground configuration ions predominantly excited in hotter laser-produced plasma. The most intense lines of the 4d104f2–4d104f5d transitions in the Gd XVII and Tb XVIII spectra were classified for the first time.

4p64d8–(4d75p + 4d74f + 4p54d9) Transitions in Xe XI

The spectrum of ten times ionized xenon, Xe XI, was observed in the region 105–157 A with a low-inductance vacuum spark and a 10.7 m grazing-incidence spectrograph. About 200 lines belonging to the 4d8–(4d75p + 4d74f + 4p54d9) transition array were observed. 140 of these lines are in the region 130–140 A, which is of importance for extreme ultraviolet (EUV) lithography. The spectrum was interpreted by means of Hartree–Fock calculations and orthogonal parameters using scaling factors for the energy parameters obtained by extrapolation along the Rh II isoelectronic sequence. All 9 levels of the 4d8 configuration and 123 levels of the 4d75p + 4d74f + 4p54d9 configurations were established. Transition probabilities for all observed lines were calculated with fitted values of the energy parameters. A value of 1847200 ± 1600 cm-1 (229.02 ±0.20 eV) was obtained for the ionization energy.

Analysis of the 4d9 −4d8 (4f + 6p) transition array of Sn VI

The spectrum of tin was photographed in the 150-250 A region on a 10.7 m spectrograph at the NIST Laboratory in Gaithersburg, USA, and the 3 m spectrograph in Troitsk, Russia, using a triggered spark source. In the 4d9 −4d8 (4f + 6p) transition array of Sn VI spectrum 85 lines have been classified. Sixty-three levels belonging to the 4d84f and 4d86p configurations have been established. Parametric least-squares-fitting calculations including configuration interaction between the 4d8(5p + 6p + 4f + 5f + 6f) and 4p54d10 configurations were carried out to interpret the observed spectrum adequately.

The spectrum of seven times ionized tungsten (W VIII) relevant to tokamak divertor plasmas

Tungsten spectra excited in the vacuum sparks of different setups and electric circuits were recorded on two high-resolution vacuum spectrographs. For the region 190?500??, a 10?m normal incidence spectrograph with a 3600?lines/mm grating was used in the Meudon Observatory. In the region below 350??, a set of spectra was produced using a 3?m grazing incidence spectrograph with a 3600?lines/mm grating in the Institute of Spectroscopy in Troitsk. A total of 187 lines in the region 160?271?? were identified as transitions to the low-lying odd configurations 4f135s25p6 and 4f145s25p5 from the interacting excited even 4f125s25p65d?+?4f135s25p5(5d?+?6s)?+?4f145s25p4(5d?+?6s)?+?4f145s5p6 configurations. It was found that 4f135s25p6 2F7/2 is the ground level of W VIII. The fine structure splitting and relative positions of the odd terms were established, and 98 levels of the excited even configurations were found.

A STUDY OF THE 5D2, 5D6P AND 5D5F CONFIGURATIONS OF PT IX

The spectrum of eight-times ionized platinum was photographed in the 100-400 A region using a 2-m and a 10-m grazing incidence spectrographs. The 5d2-(5d6p + 5d5f) transitions of Pt IX were analysed and 116 lines have been classified in the 216-345 A region. All nine levels of the 5d2 configuration, all twelve levels of the 5d6p configuration and eighteen of twenty levels of the 5d5f configuration have been established. Hartree-Fock and least-squares fitted parametric calculations were carried out and they interpret the observed level structure quite satisfactorily.

The analysis of the 5d3, 5d26s and 5d26p configurations of quadruply ionized rhenium (Re V)

The spectrum of rhenium was photographed in the 300-2000 A region on a 3m normal incidence spectrograph using a triggered spark and a sliding spark source. The (5d3 + 5d26s)–5d26p transitions of Re V were analysed. All 19 levels of the 5d3 configuration, 15 of 16 levels of the 5d26s configuration and all 45 levels of the 5d26p configuration have been established. 381 lines have been classified in Re V. The least-squares-fitted (LSF) and Hartree-Fock (HF) calculations satisfactorily interpret the spectrum.

4f135s25p6-4f135s25p56s transitions in the W VIII spectrum and spectra of isoelectronic hafnium, tantalum, and rhenium ions

Spectra of hafnium, tantalum, tungsten, and rhenium in the range of 145–350Å, excited in a low-inductive vacuum spark, have been recorded on a grazing-incidence vacuum spectrograph using a grating with 3600 lines/mm and a radius of 3 m. The wavelengths and intensities of more than 3800 lines in the tungsten spectrum have been measured. Comparison with the Hartree-Fock calculations showed that most spectral lines should be due to transitions in the W VIII spectrum. Short-wavelength lines due to the 4f135s25p6-4f135s25p56s transitions have been identified in the W VIII spectrum and the Re IX, Ta VII, and Hf VI isoelectronic spectra.

Analysis of the 3d44f configuration in Ni VI

The 3d5?3d44f transitions in the Ni VI spectrum excited in the vacuum spark and sliding spark sources were analysed. 187 spectral lines were classified in the 150?185?? wavelength region with the aid of a Cowan Computer Code and 104 energies of 3d44f configuration were determined. The interaction effects between 3d44f, 3d45p and 3p53d6 configurations in Ni VI were discussed. The strongest 3d5 6S?3d44f 6P transitions were also classified in the isoelectronic Cu VII and Zn VIII spectra.

Analysis of the 3d 3 4f configuration in Ni VII

The 3d4-3d34f transitions in Ni VII excited in vacuum spark and sliding spark sources and photographed with a high resolution were analyzed. Approximately 250 spectral lines were classified in the 127-158-A wavelength region, and 134 energies of 3d34f configuration were determined. The effects of interaction of the 3d4-3d34f configuration with the 3p53d5 and 3d35p configurations in Ni VII have been discussed. The parametric least-squares-fitting calculations by use of a Cowan computer code in the frame of Hartree-Fock method have confirmed the results of the present analysis.

The analysis of the 4d9-(4d84f + 4d86p) transitions of Cd IV

The spectrum of cadmium was photographed in the 300-380 ? wavelength region on a 3-m grazing incidence spectrograph (36001/mm grating) and on a 10.7 m grazing incidence spectrograph (12001/mm grating). A triggered spark was used as an excitation source in each case. The 4d9-4d8(4f + 6p) transitions in Cd IV were analysed. Sixty-seven levels (out of 126 total levels) of the two excited configurations have been established. One hundred and one lines have been classified. The spectrum has been satisfactorily described by configuration interaction calculations involving the 4d8np (n = 5, 6), 4d8nf (n = 4, 5, 6) and 4p54d10 configurations.