Relativistic Calculations of Transition Amplitudes in the Helium Isoelectronic Sequence

Johnson, W. R.; Plante, D. R.; Sapirstein, J.

doi:10.1016/s1049-250x(08)60165-2

Cited by 196 publications

(198 citation statements)

References 76 publications

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“…Using a shielded channeltron detector, the transition rate for the 2 3 P 2 decay to the ground state was determined relative to the (now known) count rate of the XUV photons emitted via 2 3 P 1 decay to the ground state, with an absolute uncertainty of 5% (Hodgman et al, 2009a). This was again in excellent agreement with the same QED frameworks as before (Drake, 1969;Johnson and Plante, 1995;Lach and Pachucki, 2001), and was able to discount several others. An upper bound was also placed on the 2 3 P 0 decay rate of 0.01 s −1 as determined by the channeltron background count rate.…”

Section: Spectroscopic Measurements Of Atomic Properties a Metasmentioning

confidence: 57%

Cold and trapped metastable noble gases

et al. 2012

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We review experimental work on cold, trapped metastable noble gases. We emphasize the aspects which distinguish work with these atoms from the large body of work on cold, trapped atoms in general. These aspects include detection techniques and collision processes unique to metastable atoms. We describe several experiments exploiting these unique features in fields including atom optics and statistical physics. We also discuss precision measurements on these atoms including fine structure splittings, isotope shifts, and atomic lifetimes.

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Section: Spectroscopic Measurements Of Atomic Properties a Metasmentioning

confidence: 57%

Cold and trapped metastable noble gases

et al. 2012

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“…A precise rate for the 2 3 P 0 → 2 3 S 1 (E 1 ) transition is given in Ref. [3]. For comparison with experiment, our two-photon line shape should be added to the Lorentzian obtained using the accurate line width and the single-photon transition rate.…”

Section: Appendix: Analysis Of the Line Shapementioning

confidence: 99%

“…In recent years, accurate calculations of decay rates of 2 3 P 0 states of heliumlike ions have been performed for nuclear charges Z ≤ 94, with [1,2] and without [3] consideration of hyperfine quenching. Single photon decay of the 2 3 P 0 state to the ground state is strictly forbidden by angular momentum selection rules and only a weak E1 decay to the 2 3 S 1 state or an even weaker M1 decay to the 2 3 P 1 state is possible for isotopes with nuclear spin I = 0.…”

Section: Introductionmentioning

confidence: 99%

Two-photonE1M1decay of23P0s

2002

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Two-photon E1M1 transition rates are evaluated for heliumlike ions with nuclear charges in the range Z = 50-94. The two-photon rates modify previously published lifetimes/transition rates of 2 3 P0 states. For isotopes with nuclear spin I = 0, where hyperfine quenching dominates the 2 3 P0 decay, two-photon contributions are significant; for example, in heliumlike 187 Os the two-photon correction is 3% of the total rate. For isotopes with I = 0, where the 2 3 P0 decay is unquenched, the E1M1 corrections are even more important reaching 60% for Z=94. Therefore, to aid in the interpretation of experiments on hyperfine quenching in heliumlike ions and to provide a more complete database for unquenched transitions, a knowledge of E1M1 rates is important.

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“…The systematic A&A 592, A141 (2016) theoretical studies are mostly confined to the n = 2 complex (e.g., Drake 1988;Chen et al 1993;Cheng et al 1994;Plante et al 1994;Johnson et al 1995;Cheng & Chen 2000;Artemyev et al 2005). There are also some large-scale calculations involving n > 2 singly excited levels of helium-like ions.…”

Section: Introductionmentioning

confidence: 99%

Energy levels and transition rates for helium-like ions withZ = 10–36

Guo

Wang

et al. 2016

A&A

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Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate energies for the lowest singly excited 70 levels among 1snl (n ≤ 6, l ≤ (n − 1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln l (n ≤ 6, l ≤ (n − 1)) configurations of helium-like ions with Z = 10−36. Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions. Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n ≥ 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics.

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Relativistic Calculations of Transition Amplitudes in the Helium Isoelectronic Sequence

Cited by 196 publications

References 76 publications

Cold and trapped metastable noble gases

Cold and trapped metastable noble gases

Two-photonE1M1decay of23P0s

Energy levels and transition rates for helium-like ions withZ = 10–36

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