E Ya Kononov

A Detailed Analysis of the n=3 – n'=3 Transitions in the Mg-like Ions FeXV, CoXVI and NiXVII

Laser produced spectra of iron, cobalt and nickel were obtained using the 6.65 m normal incidence vacuum spectrograph with a short-wave blazed 1200 lines/mm grating. Transitions between the configurations 3s2, 3s3p, 3p2, 3s3d and 3p3d of the Mg-like ions FeXV, CoXVI and NiXVII were studied in the region 170-600 A. Singlet-triplet connections were found for these ions. The previous identifications were revised and 60 new lines, mainly from the 3p3d configuration, were found. Wavelengths were remeasured and related energy levels were improved. New identifications of solar flare lines are proposed on the basis of this work.

Analysis of the 3s-3p and 3p-3d Transitions of S VII from Laser Plasma

Forty lines of S VII in the 601-1103 A wavelength range are identified as transitions between the 2p53s, 3p and 3d configurations. All energy levels in these configurations are determined. Their identification is confirmed by the results of a parametric calculation and an isoelectronic comparison.

Spectra of Very Highly Ionized Atoms

Recent laboratory investigations of the spectra of highly ionized atoms are reviewed. These include some interpretations of X-ray and VUV spectra of elements heavier than iron. New theoretical data are compared with experimental ones. The possible accuracy of wavelength measurements for spectra produced with specified light sources is discussed.

Energy Levels of the 4lj and 5lj States for Cu-like Ions; Experiment and Calculation

Wavelengths of 4-5 and 4-4 transitions have been measured experimentally for the Cu-like ions Ag XIX-Sn XXII (Z = 47-50). The Relativistic Model Potential Method has been used for extrapolation and interpolation of the 4lj and 5lj energy levels in the range Z = 36-80. Two versions of calculations were made. In the first one the experimenal energies for Z = 36, 42, 56, 62 were used as references; these results are in good agreement with the new experimental data are used to obtain more accurate calculated values for large Z.

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.

4d95p2 configuration in the spectra of in III-Te VI

The radiative 4d105p-4d95p2 transitions in the spectra of the In III, Sn IV, Sb V and Te VI, ions, belonging to the silver isoelectronic sequence, have been investigated in the range 250–600 Å with high resolution. The energies of most levels of the 4d95p2 configuration with J = 1/2, 3/2, and 5/2, involved in the transitions to the 4d105p configuration, are found. Along the isoelectronic sequence, the 4d95p2 configuration passes from the position below the ionization limit 4d10 in Te VI to the position above this limit in In III with corresponding autoionization effects. The autoionization widths of levels are measured. The data obtained are compared with the results of calculations by the Hartree-Fock and semiempirical methods.

Highly excited and autoionizing states in the spectrum of triply ionized titanium Ti(IV)

The spectrum of Ti(IV) excited in a vacuum spark was investigated in the range 250–900 Å with high resolution. Eighty-four lines were measured and identified as transitions from the 3p6ns, 3p6np, and 3p6nf configurations, where n ≤ 8, ≤ 10, and ≤ 8, respectively, and from the 3p53d2 and 3p53d4s configurations. The lines due to the transitions from the autoionizing levels of the 3p53d2 and 3p53d4s configurations were also observed and their widths were measured. The experimental data were compared with the results obtained by calculations using the Hartree-Fock method and semiempirical calculations.

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.

Spectra of Highly Ionized Atoms in Hot Plasmas: Conditions for Production and Observation

Excitation conditions for spectra of highly ionized atoms in the low inductance vacuum spark and laser produced plasma are discussed in this review from the view-point of obtaining accurate numerical data on energy structure of electron shells. Some optimum observation conditions and data acquisition methods are suggested.

Autoionizing and highly excited states in the spectrum of triply ionized tin Sn IV

Transitions from autoionizing states in the spectrum of Sn IV in the range 200–630 Å, occurring due to the excitation of electrons from the inner 4d10 shell, are investigated with high resolution. The transitions from the 4d95p2, 4d95s6p, and 4d95snf (up to n = 9) configurations are identified and their autoionization widths are measured. Transitions from the highly excited 4d10ns (n = 8–10), 4d106p, and 4d107d configurations are also revealed and the ionization potential of Sn IV is refined. The data obtained are compared with the results of calculations by the Hartree-Fock and semiempirical methods.