Ge-like Ions Research Articles

Ionization energies of Ge-like ions from Kr V to Pd XV

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.

Energy Levels, Wavelengths, and Transition Probabilities of Intercombination Lines in the Spectra of Gе-Like I, Cs, and La Ions

Energy levels, wavelengths, transition probabilities, and line strengths are calculated for the allowed electric dipole 4s24p2–4s4p3 and 4s24p2–4s24p4d transitions of Ge-like ions with Z = 53, 55 and 57, I XXII, Cs XXIV, and La XXVI. By employing active-space techniques to expand the confi guration list, we also include the Breit interaction and quantum electrodynamical (QED) effects to correct the atomic state wave functions and the corresponding energies. Both valence correlation and core polarization effects are included. The results are compared with the available experimental and other theoretical results.

Intercombination Transitions in the n = 4 Shell of Zn-, Ga-, and Ge-Like Ions of Elements Kr through Xe

Earlier beam-foil measurements have targeted 4s-4p intercombination transitions in the Zn-, Ga- and Ge-like ions of Nb (Z=41), Mo (Z=42), Rh (Z=44), Ag (Z=47) and I (Z=53). At the time, the spectra were calibrated with literature data on prominent lines in the Cu- and Zn-like ions. Corresponding literature data on the intercombination transitions in Ga- and Ge-like ions were largely lacking, which caused some ambiguity in the line identifications. We review the (mostly computational) progress made since. We find that a consistent set of state-of-the-art computations of Ga- and Ge-like ions would be highly desirable for revisiting the beam-foil data and the former line identifications for the elements from Kr (Z=36) to Xe (Z=54). We demonstrate that the literature data for these two isoelectronic sequences are insufficient, and we contribute reference computations in the process. We discuss the option of electron beam ion trap measurements as an alternative to the earlier use of classical light sources, beam-foil interaction and laser-produced plasmas, with the example of Xe (Z=54).

Energies and Spectral Lines for the States of 4s 24p 2, 4s4p 3, and 4s 24p4d Configurations in Ge-Like Te, Xe, and Ba Ions

The energy levels, wavelengths, transition rates, and line strengths have been calculated for the 4s 24p 2–4s4p 3 and 4s 24p 2–4s 24p4d allowed transitions occurring within the ground configuration (4s 24p 2) in the heavy Ge-like Te, Xe, and Ba ions. The fully relativistic multiconfiguration Dirac–Hartree–Fock method taking into account both correlations within the n = 5 complex and the QED effects has been used in the calculations. The calculation results are found to agree well with the data obtained on the TFR tokamak and by recent EBIT measurements in Xe. The isoelectronic sequence of the Ge-like ions is important in nuclear fusion research as their spectra may provide diagnostic information on magnetically confined plasmas.

Energies and transition rates in Ge-like ions between In XVIII and Ce XXVII

The energy levels, wavelengths, oscillator strengths, and radiative electric dipole (E1), magnetic quadrupole (M2) transition probabilities for Ge-like ions (49≤Z≤58) among the lowest 88 fine-structure levels belonging to the ([Ar] 3d10)4s24p2, ([Ar] 3d10)4s24p4d, ([Ar] 3d10)4s4p3, ([Ar] 3d10)4s4p24d, ([Ar] 3d10)4s24d2, and ([Ar] 3d10)4p4 configurations are calculated using the fully relativistic multiconfiguration Dirac–Fock (MCDF) approach including the correlations within the n=7 complex, Breit interaction (BI) and quantum electrodynamics (QED) effects. For comparison, an independent calculation using the many-body perturbation theory (MBPT) method is also carried out to confirm the present energy levels accuracy, taking Xe XXIII as an example. The present results are compared with available experimental and theoretical results and good agreement is obtained. These accurate theoretical data are useful for controlled thermonuclear fusion research, plasma physics, and astrophysical applications.

EUV beam-foil observations of Cu-like ions through Ge-like ions of iodine

Extreme ultraviolet (EUV) observations of foil-excited ion beams have been extended up to iodine (Z=53). Lines from Cu- and Zn-like ions of iodine served to calibrate the spectra. Nearby lines have the signature pattern of the intercombination line multiplet in Ga-like ions. Candidates for the two triplet–quintet intercombination lines in the Ge-like ion are proposed. Prompt and delayed spectra as well as decay curves support the proposed identifications.

Extreme-ultraviolet spectra of highly charged Pt ions with several valence-shell electrons: Observation and accurate calculations

Previous observations of Cu- through Ge-like high-$Z$ ions have demonstrated that accurate measurements and theory agree well for ions with a single valence electron but that additional electrons in the valence shell cause progressively worsening computational problems. We have obtained highly resolved euv spectra of Pt ($Z=78$) ions in an electron-beam ion trap. The measured wavelengths are compared to the results of a number of recent large-scale calculations, including our own multireference M\o{}ller-Plesset computations. The latter calculations match the best for Cu- and Zn-like ions and represent an order-of-magnitude improvement in predictive accuracy for Ga- and Ge-like ions.

Energy levels, transition rates and lifetimes for low-lying levels in Cu-, Zn-, Ga- and Ge-like ions of iodine

Energies of low-lying levels, transition energies and rates of ground state transitions in Cu- through Ge-like ions of iodine have been calculated using the GRASP2K package, which is based on the multiconfiguration Dirac–Fock method. Wavelength and level lifetime results are employed to interpret prompt and delayed beam-foil spectra in the extreme ultraviolet.

Relativistic atomic data for EUV and X-ray spectra of highly charged Cu-, Zn-, Ga- and Ge-like ions (70 ≤ Z ≤ 92)

Wavelengths and transition probabilities have been calculated for the n=4, δn=0 allowed transitions in the heavy Cu-, Zn-, Ga- and Ge-like ions with Z=70–92. Fully relativistic multiconfiguration Dirac-Fock (MCDF) computations were carried out. The present results are compared to and agree well with recent electron-beam ion-trap (EBIT) measurements in Yb, W, Os, Au, Pb, Bi, Th and U ions.

Wavelengths and transition probabilities in heavy Ge-like ions (70 ⩽ Z ⩽ 92)

Wavelengths and transition probabilities have been calculated for the 4s 24p 2–4s4p 3 and 4s 24p 2–4s 24p4d allowed transitions and for the forbidden (M1 and E2) transitions occurring within the ground configuration (4s 24p 2) in the heavy Ge-like ions with Z = 70–92. The fully relativistic multiconfiguration Dirac–Fock method taking into account both the correlations within the n = 4 complex and the QED effects has been used for the calculations. The present results are compared to and agree well with recent electron-beam ion-trap measurements in tungsten, osmium, gold, bismuth, thorium, and uranium.

Excitation-autoionization cross-sections and rate coefficients for Ge-like ions

Excitation-autoionization cross-sections and rate coefficients for Ge-like ions

Analysis of X-ray spectra from laser-irradiated high- Z targets

The X-ray spectra of highly ionized hafnium, tantalum, tungsten and rhenium have been observed in laser-produced plasmas. Isolated peaks were found in the 3.6 to 5 Å region. A detailed analysis of these peaks has been performed by using the spin-orbit-split array model of Bauche-Arnoult et al. Besides the resonance lines in the Ni-like ions, the 3d- nf transition bands in Cu-like through Ge-like ions were identified.

Wavelengths and transition probabilities of intercombination lines in the spectra of Ga- and Ge-like Ag ions

Prompt and delayed EUV spectra of foil-excited Ag have been recorded at ion energies of 19 and 25 MeV. The recent identifications of intercombination transitions in Ga- and Ge-like Ag ions are corroborated by spectra recorded with higher resolution than before and by lifetime measurements. Lifetime results for the resonance transitions of Cu-like ions and for the intercombination transitions in Zn- to Ge-like ions are compared with theoretical predictions.

Addition to the analysis of the Sr VI and Sr VII spectra

Fifty-six lines of multicharged strontium are measured with an improved wavelength accuracy, or interpreted for the first time. They are 4p4s, 4p5s and 4p4d transitions in Sr VII and 4p5s transitions in SrVI. The revision of the singlet-triplet connection in SrVII is supported by theoretical survey of the ground configuration in Ge-like ions.

X-ray spectroscopy of high-Z materials

The spectra of laser-produced plasmas of various materials of Z>70 have been interpreted as spin-orbit-split arrays of the 3d – 4f and 3d – 5f transitions for Ni-like to Ge-like ions. The excellent agreement between the model and the experiments indicated the possibility of their use for plasma diagnostics. First results from targets of Gold alloyed with Aluminium give an alternative diagnostic.