Precision spectroscopy of trapped highly charged heavy elements: pushing the limits of theory and experiment

Gillaspy, John D.

doi:10.1088/0031-8949/89/11/114004

Cited by 11 publications

(10 citation statements)

References 53 publications

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“…We also present the most pronounced spectral lines of the Na-like, Mg-like and Al-like yttrium charge states, as these can provide benchmark experimental results for precise multi-electron atomic theory calculations. Na-like D1 and D2 lines originate from quasi-hydrogenic ions and have been used as a probe of QED contributions due to their high intensities and the available precise ab initio calculations [6,[53][54][55]. We report the first data for the wavelengths of the Na-like D1 and D2 yttrium lines measured with an EBIT to provide accurate experimental results that complement the previously reported measurements of Reader et al [45] in laser-produced and tokamak plasmas.…”

Section: Introductionsupporting

confidence: 60%

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

Silwal

Takács

Dreiling

et al. 2017

Atoms

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Abstract:Extreme ultraviolet spectra of the L-shell ions of highly charged yttrium (Y 26+ -Y 36+ ) were observed in the electron beam ion trap of the National Institute of Standards and Technology using a flat-field grazing-incidence spectrometer in the wavelength range of 4 nm-20 nm. The electron beam energy was systematically varied from 2.3 keV-6.0 keV to selectively produce different ionization stages. Fifty-nine spectral lines corresponding to ∆n = 0 transitions within the n = 2 and n = 3 shells have been identified using detailed collisional-radiative (CR) modeling of the non-Maxwellian plasma. The uncertainties of the wavelength determinations ranged between 0.0004 nm and 0.0020 nm. Li-like resonance lines, 2s-2p 1/2 and 2s-2p 3/2 , and the Na-like D lines, 3s-3p 1/2 and 3s-3p 3/2 , have been measured and compared with previous measurements and calculations. Forbidden magnetic dipole (M1) transitions were identified and analyzed for their potential applicability in plasma diagnostics using large-scale CR calculations including approximately 1.5 million transitions. Several line ratios were found to show strong dependence on electron density and, hence, may be implemented in the diagnostics of hot plasmas, in particular in fusion devices.

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Section: Introductionsupporting

confidence: 60%

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

Silwal

Takács

Dreiling

et al. 2017

Atoms

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“…A controversy arising from a claimed Z-dependent divergence between earlier experimental data and calculations (Chantler et al, 2013(Chantler et al, , 2012Gillaspy, 2014), soon disputed by Epp (2013), has been settled, with all newer results agreeing very well both with older calculations and advanced theory (Artemyev et al, 2005). Nonetheless, better measurements will be needed to test higherorder QED as well as interelectronic contributions to the binding energy in more detail.…”

Section: Lamb-shift Studies In the X-ray Regionmentioning

confidence: 99%

Highly charged ions: Optical clocks and applications in fundamental physics

et al. 2018

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Recent developments in frequency metrology and optical clocks have been based on electronic transitions in atoms and singly charged ions as references. The control over all relevant degrees of freedom in these atoms has enabled relative frequency uncertainties at a level of a few parts in 10 −18 . This accomplishment not only allows for extremely accurate time and frequency measurements, but also to probe our understanding of fundamental physics, such as a possible variation of fundamental constants, a violation of the local Lorentz invariance, and the existence of forces beyond the Standard Model of Physics. In addition, novel clocks are driving the development of sophisticated technical applications. Crucial for applications of clocks in fundamental physics are a high sensitivity to effects beyond the Standard Model and Einstein's Theory of Relativity and a small frequency uncertainty of the clock. Highly charged ions offer both. They have been proposed as highly accurate clocks, since they possess optical transitions which can be extremely narrow and less sensitive to external perturbations compared to current atomic clock species. The large selection of highly charged ions in different charge states offers narrow transitions that are among the most sensitive ones for a change in the finestructure constant and the electron-to-proton mass ratio, as well as other new physics effects. Recent experimental advances in trapping and sympathetic cooling of highly charged ions will in the future enable advanced quantum logic techniques for controlling motional and internal degrees of freedom and thus enable high accuracy optical spectroscopy. Theoretical progress in calculating the properties of selected highly charged ions has allowed the evaluation of systematic shifts and the prediction of the sensitivity to the "new physics" effects. New theoretical challenges and opportunities emerge from relativistic, quantum electrodynamics, and nuclear size contributions that become comparable with interelectronic correlations. This article reviews the current status of theory and experiment in the field, addresses specific electronic configurations and systems which show the most promising properties for research, their potential limitations, and the techniques for their study.

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“…It involves ion traps [38,39] and storage rings [40,41,42] where very low densities -sometimes single ions -of highly charged plasma can be studied. This opens up the possibility to probe exotic processes in ionssuch as forbidden and unexpected transitions from states with lifetimes of up to seconds or even hours [19].…”

Section: Complementing Experimentsmentioning

confidence: 99%

“…. , n N l N } is the set of N principal and orbital quantum numbers that define the configuration (39) and γ denotes the complete set of the coupling tree quantum numbers specifying unambiguously the considered configuration state (see (50)). Then…”

Section: Z-dependent Perturbation Theorymentioning

confidence: 99%

Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions

Fischer

Godefroid

Brage

et al. 2016

J. Phys. B: At. Mol. Opt. Phys.

269

231

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Abstract. Multiconfiguration wave function expansions combined with configuration interaction methods are a method of choice for complex atoms where atomic state functions are expanded in a basis of configuration state functions. Combined with a variational method such as the multiconfiguration Hartree-Fock (MCHF) or multiconfiguration Dirac-Hartree-Fock (MCDHF), the associated set of radial functions can be optimized for the levels of interest. The present review updates the variational MCHF theory to include MCDHF, describes the multireference single and double (MRSD) process for generating expansions and the systematic procedure of a computational scheme for monitoring convergence. It focuses on the calculations of energies and wave functions from which other atomic properties can be predicted such as transition rates, hyperfine structures and isotope shifts, for example.PACS numbers: 31. 31.15ag, 32.70.Cs

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Precision spectroscopy of trapped highly charged heavy elements: pushing the limits of theory and experiment

Cited by 11 publications

References 53 publications

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

Highly charged ions: Optical clocks and applications in fundamental physics

Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions

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