We use experimental energies of the 4p5s configurations in the Ge-like ions Kr V-Pd XV to derive improved values for the ionization energies. The ionization energies of these ions are presently only roughly known, mainly through the Dirac-Fock calculations of Rodrigues et al., At Data and Nucl Data Tables 2004;86:117. They have relatively large uncertainties. By using the observed energies of the 4p5s configurations as the starting point, we eliminate a large portion of the uncertainty. Based on observations at NIST with a 10.7-m grazing-incidence grating spectrograph, we also provide improved values for some of the energy levels.

Extreme ultraviolet spectra of highly charged tungsten ions were produced with an electron beam ion trap at the National Institute of Standards and Technology and recorded with a flat-field grazing-incidence spectrometer. The spectra were measured in the wavelength range 2.7–17.3 nm while the beam energy varied between 1.65 and 2.00 keV. At these energies, the ionization stages from Zr-like W34+ to Se-like W40+ ions were observed. Large-scale collisional-radiative modelling was used to identify the strong lines, including 15 new ones, which represent electric dipole n = 4–4 transitions in these ions. While a good quantitative agreement between theoretical and experimental data was found for almost all ions, some of the tentatively identified wavelengths in W35+ significantly disagree from all available calculations.

The spectrum of seven-times ionized yttrium, Y VIII, was photographed with a sliding-spark discharge and a 10.7-m grazing-incidence spectrograph. The region of observation was 219-589 angstrom. Previous results for the 4s(2)4p(2) ground configuration and excited configurations 4s4p(3) and 4s(2)4p5s were confirmed. Previous results for the 4s(2)4p4d configuration were partially confirmed. New levels were found for the 4s(2)4p4d and 4p(4) configurations, bringing the total analysis to 70 lines and 32 energy levels. The observed configurations were interpreted with Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. Transition probabilities for the observed lines were calculated with the fitted parameters. By using the observed 4s(2)4p5s energy levels and a semi-empirical value for the effective quantum number n*(4s(2)4p5s), a new value was determined for the ionization energy: 1,033,340 +/- 1000 cm(-1) (128.12 +/- 0.12 eV). (C) 2018 Elsevier Ltd. All rights reserved.

New wavelength measurements in the vacuum ultraviolet (VUV), ultraviolet and visible spectral regions have been combined with available literature data to refine and extend the description of the spectrum of singly ionized copper (Cu II). In the VUV region, we measured 401 lines using a concave grating spectrograph and photographic plates. In the UV and visible regions, we measured 276 lines using a Fourier-transform spectrometer. These new measurements were combined with previously unpublished data from the thesis of Ross, with accurate VUV grating measurements of Kaufman and Ward, and with less accurate older measurements of Shenstone to construct a comprehensive list of ≈2440 observed lines, from which we derived a revised set of 379 optimized energy levels, complemented with 89 additional levels obtained using series formulas. Among the 379 experimental levels, 29 are new. Intensities of all lines observed in different experiments have been reduced to the same uniform scale by using newly calculated transition probabilities (A-values). We combined our calculations with published measured and calculated A-values to provide a set of 555 critically evaluated transition probabilities with estimated uncertainties, 162 of which are less than 20%.

We carried out a new analysis of the spectrum of fi ve-times-ionized zirconium Zr VI. For this we used sliding-spark discharges together with normal- and grazing-incidence spectrographs to observe the spectrum from 160 to 2000 Å. These observations showed that the analysis of this spectrum by Khan et al ( 1985 Phys. Scr. 31 837 ) contained a signi fi cant number of incorrect energy levels. We have now classi fi ed ∼ 420 lines as transitions between 23 even-parity levels 73 odd-parity levels. The 4s 2 4p 5 , 4s4p 6 , 4s 2 4p 4 4d, 5s, 5d, 6s con fi gurations are now complete, although a few levels of 4s 2 4p 4 5d are tentative. We determined Ritz-type wavelengths for ∼ 135 lines from the optimized energy levels. The uncertainties range from 0.0003 to 0.0020 Å. Hartree – Fock calculations and least-squares fi ts of the energy parameters to the observed levels were used to interpret the observed con fi gurations. Oscillator strengths for all classi fi ed lines were calculated with the fi tted parameters. The results are compared with values for the level energies, percentage compositions, and transition probabilities from recent ab initio theoretical calculations. The ionization energy was revised to 777 380  ±  300 cm − 1 ( 96.38  ±  0.04 eV ) .

The spectrum of a platinum hollow-cathode lamp containing neon carrier gas was recorded photographically and photoelectrically with a 10.7 m normal-incidence vacuum spectrograph. Wavelengths and intensities were determined for about 5600 lines in the region 1130-4330 A. An atlas of the spectrum is given, with the spectral lines marked and their intensities, wavelengths, and classifications listed. Lines of impurity species are also identified. The uncertainty of the photographically measured wavelengths is estimated to be ± 0.0020 A. The uncertainty of lines measured in the photoelectric scans is 0.01 A for wavelengths shorter than 2030 A and 0.02 A for longer wavelengths. Ritz-type wavelengths are given for many of the classified lines of Pt II with uncertainties varying from ±0.0004 to ± 0.0025 A. The uncertainty of the relative intensities is estimated to be about 20%.

The analysis of the spectrum of four-times-ionized yttrium, Y V, was extended to provide a large number of new spectrum lines and energy levels. The new analysis is based on spectrograms made with sliding-spark discharges on 10.7 m normal- and grazing-incidence spectrographs. The measurements cover the region 184–2549 Å. The results revise levels for this spectrum by Zahid-Ali et al. (1975) and by Ateqad et al. (1984). Five hundred and seventy lines were classified as transitions between 23 odd-parity and 90 even-parity levels. The 4s24p5, 4s4p6, 4s24p44d, 5s, 5p, 5d, 6s configurations are now complete. Results for the 4s24p46d and 7s configurations are tentative. Ritz-type wavelengths were determined from the optimized energy levels, with uncertainties as low as ±0.0004 Å. The observed configurations were interpreted with Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. Oscillator strengths for all classified lines were calculated with the fitted parameters. The results are compared with values for the level energies, percentage compositions, and transition probabilities from recent ab initio theoretical calculations. The ionization energy was revised to 607,760 ± 300 cm−1 (75.353 ± 0.037 eV).

The spectrum of quadruply-ionized molybdenum Mo V was observed from 200 to 4700 angstrom with sliding spark discharges on 10.7 m normal-and grazing-incidence spectrographs. The existing analyses of this spectrum (Tauheed et al 1985 Phys. Scr. 31 369; Cabeza et al 1986 Phys. Scr. 34 223) were extended to include the 5s(2), 5p(2), 5s5d, 5s6s, 4d5f, and 4d5g configurations as well as the missing H-3(6) level of 4d4f and about 75 levels of the core-excited configuration 4p(5)4d(3). The values of the 4d5d S-1(0), 5s5p P-1(1), and 4d6p P-3(0) levels were revised. There are now about 900 lines classified as transitions between 66 even parity and 191 odd parity energy levels. Of these, about 600 lines and 130 levels are new. From the optimized energy level values, Ritz-type wavelengths were determined for about 380 lines, with uncertainties varying from 0.0003 to 0.002 angstrom . The observed configurations were theoretically interpreted by means of Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. The fitted parameters were used to calculate oscillator strengths for all classified lines. A few unclassified lines and undesignated levels are also given. An improved value for the ionization energy was obtained by combining the observed energy of the 4d5g configuration with an ab initio calculation of its term value. The adopted value is 438 900 +/- 150 cm(-1) (54.417 +/- 0.019 eV).

We report spectroscopic measurements of highly charged samarium and erbium performed at the National Institute of Standards and Technology electron beam ion trap (EBIT). These measurements are in the extreme ultraviolet range, and span electron beam energies from 0.98 keV to 3.00 keV. We observed 71 lines from Kr-like Sm26+ to Ni-like Sm34+, connecting 83 energy levels, and 64 lines from Rb-like Er32+ to Ni-like Er40+, connecting 78 energy levels. Of these lines, 64 in Sm and 60 in Er are new. Line identifications are performed using collisional-radiative modeling of the EBIT plasma. All spectral lines are assigned individual uncertainties, most in the similar to 0.001 nm range. Energy levels are derived from the wavelength measurements.

This paper summarizes work at the National Institute of Standards and Technology (NIST) in support of the International Atomic Energy Agency (IAEA) Coordinated Research Project on "Light Element Atom, Molecule and Radical Behaviour in the Divertor and Edge Plasma Regions." It includes numerical data on radiative transition rates for ions of fluorine and neon critically compiled at NIST.

Extreme ultraviolet spectra of highly charged barium atoms were produced with an electron beam ion trap (EBIT) and recorded with a flat-field grazing-incidence spectrometer. The spectra were measured in the wavelength range 4 nm–24 nm with the beam energies varying from 700 eV to 30 000 eV. The line identifications were performed with collisional-radiative modeling of the EBIT plasma that provided good quantitative agreement between simulated and measured spectra. In the energy range 700 eV–1750 eV, fifty three n = 4–n = 4 transitions in Se-like (Ba22+) to Cu-like (Ba27+) ions were identified, with forty seven corresponding to new lines. Almost all lines are due to electric-dipole transitions. For the beam energies of 3945 eV–7530 eV, we identified eight new n = 3–n = 3 transitions in Ba42+ (Si-like), Ba43+ (Al-like), and Ba44+ (Mg-like). At the highest beam energy, 30 000 eV, three new n = 2–n = 2 transitions of Ba51+ (B-like), Ba52+ (Be-like), and Ba53+ (Li-like) were identified. The measured wavelengths are compared with recent ab initio theoretical calculations. An improved ionization energy for Ba26+ (Zn-like), IE = 937.2 ± 0.8 eV, was determined by comparing theoretical values with measurements along the Zn isoelectronic sequence.

Extreme ultraviolet radiation emitted from highly-charged dysprosium ions was measured at the National Institute of Standards and Technology. The ions were created, trapped, and excited in an electron beam ion trap (EBIT), and the spectra were recorded with a flat-field grazing-incidence spectrometer in the wavelength range 3 nm to 17 nm. Tuning the electron beam energies between 1.2 keV and 2.0 keV resulted in a selection of Rb-like Dy29+ to Ni-like Dy38+ ions. Identification of strong n = 4-n = 4 transitions was achieved by collisional-radiative modeling of the EBIT plasma. A total of 64 spectral lines were recorded, including 54 new identifications.

We observed and analysed the extreme-ultraviolet spectra of highly charged ions of Kr XXI-Kr XXXIV produced in an electron beam ion trap (EBIT). The beam energies varied between 1.1 and 30 keV, and the wavelengths were observed between 3 and 17.3 nm with uncertainties of similar to 0.003 nm. Six new lines were identified, and wavelength uncertainties have been improved for twelve additional transitions. It was found that a line intensity ratio for allowed transitions 3s(2)3p-3s(2)3d in Al-like Kr XXIV strongly deviated from predictions based on statistical weighting of the excited levels. Collisional-radiative modelling showed that this effect, which is due to the magnetic-dipole transition within the ground configuration 3s(2)3p, offers sensitive diagnostics of electron density in the regime of interest to fusion tokamaks, EBITs, and other low-density plasmas.

The NIST electron beam ion trap (EBIT) was used to measure the D-1(3s-3p(1/ 2)) and D-2(3s-3p(3/2)) transitions in Na-like ions of xenon, barium, samarium, gadolinium, dysprosium, erbium, tungsten, platinum, and bismuth. The wavelengths are in the range 3-12 nm. Relativistic many-body perturbation theory calculations were carried out for the D-1 and D-2 lines for every element in the isoelectronic sequence from argon (Z = 18) to uranium (Z = 92), taking into account some higher-order terms in the quantum electrodynamics (QED) expansion. Uncertainties in the calculated values were carefully assessed by considering the uncertainties in the various contributions to the total calculated transition energies. We conclude that at the current level of accuracy, the calculated values can be taken to reliably represent the isoelectronic sequence from Z = 18 to 92. The agreement of theory and experiment for the D-1 line of bismuth (Z = 83) provides a test of QED at the level of 0.4%. Our results are also sensitive to retardation effects due to the finite speed of light and to variations in the assumed nuclear size.

We summarize progress that has been made on the determination of atomic data pertinent to the fusion energy program. Work is reported on the identification of spectral lines of impurity ions, spectroscopic data assessment and compilations, expansion and upgrade of the NIST atomic databases, collision and spectroscopy experiments with highly charged ions on EBIT, and atomic structure calculations and modeling of plasma spectra.

(Received February 22, 2013; in nal form April 29, 2013) By applying AUTOSTRUCTURE code, the energies and transitions for allowed (E1) and forbidden (E2, M1, and M2) lines for low-lying con gurations in magnesium-like tungsten (W) are studied. The electron correlation and relativistic e ects are included in computations. Good agreement between our results and available other results are found. The data for E2, M1 and M2 besides some E1 transitions for low-lying levels are presented for the rst time.