J. O. Ekberg

3s–3p, 3p–3d, and 3d–4f transitions of sodiumlike ions

New measurements have been made for wavelengths of the 3s–3p, 3p–3d, and 3d–4f transitions of the sodiumlike ions Cu18+, Zn19+, Ga20+, Ge21+, As22+, Se23+, Br24+, Kr25+, Y28+, Zr29+, Nb30+, Mo31+, Ru33+, Rh34+, Pd35+, Ag36+, and Sn39+. The measurements were made by photographing laser-produced plasmas and tokamak plasmas with grazing-incidence spectrographs. The energies of the transitions were also calculated with Dirac–Fock computer codes. By fitting the differences between the observed and calculated wave numbers to simple formulas, least-squares-fitted wavelengths for all sodiumlike ions from Ar7+ to Xe43+ were determined. The estimated uncertainty of the fitted wavelengths is ±0.007 A, which makes them useful as reference values. The wavelengths range from 9 to 713 A.

Analysis of magnesiumlike spectra from Mo XXXI to Cs XLIV

Transitions in the magnesium like ions of the elements Mo, Rh, Ag, Cd, In, Sn, Sb, I and Cs have been identified in the extreme ultraviolet spectra from laser-produced plasmas. The configurations considered are 3s2, 3s3p, 3p2, 3s3d, 3p3d, and 3d2. Based on the observations, fitted energy values of 34 levels are presented for all of the elements from Nb to Nd (Z = 41-60). The interaction of the J = 2 levels of the 3p2 and 3s3d configurations in the range Z = 45-55 is considered in detail.

Transitions in lithiumlike Cu 26+ and berylliumlike Cu 25+ of interest for x-ray laser research

Transitions in highly charged copper ions have been identified in the extreme-ultraviolet spectra from plasmas produced by the Omega laser at the University of Rochester. The 24 beams of the Omega laser were focused to separate spots of diameter 50 μm upon the surface of copper-coated targets 600 μm in diameter. The transitions in lithiumlike Cu26+ and berylliumlike Cu25+ of the type n = 3–4 were observed in the wavelength region 24 to 28 A and were bright in the focal regions. The intensities of the Cu26+ 2p–3d and 3d–4f transitions indicate that a population inversion occurs between the 3d and 4f levels. Comparisons of the observed relative intensities of the Cu26+ transitions with calculated intensities indicate that the Cu26+ spectrum originates in a plasma region with an electron density of order of 1020 cm−3 and that collisional recombination is important for populating the 4f level. The 3d–4f transitions at 25.525and 25.636 A in Cu26+, and the same transitions in neighboring elements, appear to be good candidates for achieving gain at wavelengths below the carbon absorption edge at 43.5 A.

Wavelengths and energy levels for the Na I isoelectronic sequence Y28+ through U81+

Abstract Na-like transitions from the n = 3, 4, and 5 excited levels of the ions Cd 37+ , In 38+ , Sn 39+ , and Gd 53+ were identified in the extreme ultraviolet spectra from plasmas produced by one or two beams of the Nova laser at the Lawrence Livermore National Laboratory. The currently observed wavelengths and the previously observed wavelengths for lower Z ions were compared with the wavelengths calculated using Grants multiconfiguration Dirac-Fock program. Based on this comparison, semiempirical corrections to the wavelengths were made, and the corrected wavelengths were determined for the ions Y 28+ through U 81+ . The excitation energies for the n = 3, 4, and 5 levels and the ionization energies of the ground states were also derived for the ions Y 28+ through U 81+ .

3p 6 3d 9 –3p 5 3d 10 transitions of cobaltlike ions from Sr 11+ to U 65+

The 3p63d9 2D–3p53d10 2P transitions of the Co-like ions Ru17+–Sb24+, Sm35+, Eu36+, Gd37+, Yb43+, and Au52+ were excited with laser-produced plasmas and photographed with grazing-incidence spectrographs. The observed wavelengths of the 2D5/2–2P3/2 and 2D3/2–2P1/2 transitions were compared with relativistically calculated ab initio wavelengths and, by fitting the differences between the observed and calculated wave numbers to simple formulas, least-squares fitted wavelengths were obtained for all ions from Sr11+ to U65+. The wavelengths range from 8 to 93 A. The estimated uncertainty of the fitted wavelengths is ±0.005 A, which makes them useful as reference values. Smoothed values of the energy levels were derived from the fitted values of the wavelengths and 3p63d9 2D fine-structure intervals. Wavelengths for the 3p63d9 2D3/2–3p53d10 2P3/2 transitions and the 3p63d9 2D5/2–2D3/2 magnetic-dipole transitions were derived from the smoothed energy-level values.

Transitions and energy levels for Cu-like Yb 41+ , Ta 44+ , and U 63+

Transitions from the n = 4, 5, and 6 excited levels of the Cu-like ions Yb41+, Ta44+, and U63+ were observed in the spectra from plasmas that were produced by one or two beams of the Nova laser. Wavelengths in the range 9–140 A were measured with an uncertainty of ±0.015 A and were compared with previously measured and predicted wavelengths. The energy levels were derived from the observed wavelengths.

Spectra and energy levels of Sm XXXIV, Eu XXXV, Gd XXXVI, and Yb XXXXII

We present wavelengths and energy levels based on extreme-ultraviolet and x-ray transitions in the ions Sm+33, Eu+34, Gd+35, and Yb+41 of the cu i isoelectronic sequence. The sources of the spectra were laser-produced plasmas generated by the OMEGA laser facility at the University of Rochester’s Laboratory for Laser Energetics. The photographic spectra were recoreder by a 3-m grazing-incidence spectograph. The spectra lines fall between about 10 and 115 A and we compare our results with previous measurements where available.

Transitions of the type 2s–2p in highly charged fluorinelike and oxygenlike Mo, Cd, In, and Sn

Transitions of the type 2s–2p in the F i and O i isoelectronic sequences have been identified in the extreme-ultraviolet spectra from plasmas that were produced by one beam of the Nova laser. In the F i sequence, two were observed for the ions Mo33+, Cd39+, In40+, and Sn41+. In the O i sequence, 13 transitions were transitions observed for Mo34+, 7 transitions for Cd40+, 8 transitions for In41+, and 7 transitions for Sn42+. The observed wavelengths were compared with calculated wavelengths, and predicted wavelengths are presented for the F i sequence up to atomic number Z = 64 and for the O i sequence to Z = 54.

Wavelengths for the 3s 2 1 S 0 –3s3p 3 P 1 transition of the magnesiumlike ions Fe 14+ through Nd 48+

The wavelengths of the 3s2 1S0–3s3p3P1 transition for the magnesiumlike ions Zn18+, Ge20+, Se22+, Mo30+, Sn38+, and Xe42+ have been measured in spectra from the Princeton Large Torus tokamak. When we compare these and other recently available observations with wavelengths calculated using Grant’s multiconfiguration Dirac–Fock program, wavelengths are predicted for the ions Fe14+ through Nd48+.

2l–3l ′ and 2l–4l ′ transitions in heliumlike and hydrogenlike silicon

Wavelengths are reported for the n = 2–n = 3 and n = 2–n = 4 transitions of Si xiii and Si xiv, as observed in a laser-heated plasma. The wavelength range of the observations is 24–40 A.