GRASP2018—A Fortran 95 version of the General Relativistic Atomic Structure Package

Fischer, Charlotte Froese; Gaigalas, Gediminas; Jönsson, P.; Bieroń, Jacek

doi:10.1016/j.cpc.2018.10.032

Cited by 251 publications

(88 citation statements)

References 6 publications

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“…where the summation runs over the number N of electrons and C (1) is the renormalized spherical harmonic of rank 1 [23]. The reduced matrix elements of (6) and (7) involve, respectively, sums over radial transition integrals of the kind…”

Section: Transition Parametersmentioning

confidence: 99%

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Coulomb (Velocity) Gauge Recommended in Multiconfiguration Calculations of Transition Data Involving Rydberg Series

Papoulia

Ekman

Gaigalas

et al. 2019

Atoms

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Astronomical spectroscopy has recently expanded into the near-infrared (nIR) wavelength region, raising the demands on atomic transition data. The interpretation of the observed spectra largely relies on theoretical results, and progress towards the production of accurate theoretical data must continuously be made. Spectrum calculations that target multiple atomic states at the same time are by no means trivial. Further, numerous atomic systems involve Rydberg series, which are associated with additional difficulties. In this work, we demonstrate how the challenges in the computations of Rydberg series can be handled in large-scale multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction (RCI) calculations. By paying special attention to the construction of the radial orbital basis that builds the atomic state functions, transition data that are weakly sensitive to the choice of gauge can be obtained. Additionally, we show that the Babushkin gauge should not always be considered as the preferred gauge, and that, in the computations of transition data involving Rydberg series, the Coulomb gauge could be more appropriate for the analysis of astrophysical spectra. To illustrate the above, results from computations of transitions involving Rydberg series in the astrophysically important C IV and C III ions are presented and analyzed.

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Section: Transition Parametersmentioning

confidence: 99%

“…weighted with the products of the expansion coefficients of the CSFs and the angular coefficients [20,21,23]. P (r) and P(r) are the radial functions of the large components of the Dirac one-electron spin-orbitals (2) that build the CSFs of the initial state γ π J and the final state γπ J, respectively.…”

Section: Transition Parametersmentioning

confidence: 99%

Coulomb (Velocity) Gauge Recommended in Multiconfiguration Calculations of Transition Data Involving Rydberg Series

Papoulia

Ekman

Gaigalas

et al. 2019

Atoms

View full text Add to dashboard Cite

show abstract

“…We have used GRASP2018 code based on Multiconfiguration Dirac-Fock (MCDHF) calculations and Relativistic Configuration Interaction (RCI) calculations [9]. It gave the opportunity,first time to present the relativistic calculations for Energy levels, oscillator and transition probabilities for Electric-dipole (E1) among the states of the ground 5s 2 5p 4 , and excited, 5s 2 p 3 6s and 5sp 5 configurations for six times ionized cerium.…”

Section: Introductionmentioning

confidence: 99%

Energy Levels and Transition Parameters in Ce6+ from MCDHF Model

Wajid

Jabeen

2019

Jour. Atomic Mole. Conden. Nano Phys.

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Multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and subsequent Relativistic Configuration Interaction (RCI) calculations have been performed for the 5s 2 5p 4 , 5s 2 5p 3 6s and 5s5p 5 configurations of six times ionized cerium using GRASP2018 package. The electron correlation effects, (BI) interaction and Quantum Electrodynamics (QED) effects have been considered in the calculation. Energy levels, oscillator strength and transition probabilities among the transitions of 5s 2 5p 4 , 5s5p 5 and 5s 2 5p 3 6s have been calculated. The calculated energy levels are compared with experimental data available and show good agreement with it.

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“…Γ collectively denotes all the γ k included in the representation of the Kr-or Rb-like ground state. Using two different implementations of the MCDHF method [25,26], we systematically expand the active space of virtual orbitals to monitor the convergence of the calculations and to assess their uncertainties.…”

mentioning

confidence: 99%

“…[25] uses full relaxation of all spectroscopic orbitals, and single and double excitations from all these orbitals to the free single-electron states up to 5d, with a result of 432.4(3.0) eV. In the other computation, employing [26], we generate the set of CSFs with excitations from the 3s-4d states up to 10h, with the virtual orbitals optimized layer by layer, arriving to the value 435.1(1.0) eV.…”

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confidence: 99%

Mass-Difference Measurements on Heavy Nuclides with an eV/c2 Accuracy in the PENTATRAP Spectrometer

et al. 2020

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First ever measurements of the ratios of free cyclotron frequencies of heavy, highly charged ions with Z > 50 with relative uncertainties close to 10 −11 are presented. Such accurate measurements have become realistic due to the construction of the novel cryogenic multi-Penning-trap mass spectrometer PENTATRAP. Based on the measured frequency ratios, the mass differences of five pairs of stable xenon isotopes, ranging from 126 Xe to 134 Xe, have been determined. Moreover, the first direct measurement of an electron binding energy in a heavy highly charged ion, namely of the 37th atomic electron in xenon, with an uncertainty of a few eV is demonstrated. The obtained value agrees with the calculated one using two independent, different implementations of the multiconfiguration Dirac-Hartree-Fock method. PENTATRAP opens the door to future measurements of electron binding energies in highly charged heavy ions for more stringent tests of bound-state quantum electrodynamics in strong electromagnetic fields and for an investigation of the manifestation of light dark matter in isotopic chains of certain chemical elements.

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GRASP2018—A Fortran 95 version of the General Relativistic Atomic Structure Package

Cited by 251 publications

References 6 publications

Coulomb (Velocity) Gauge Recommended in Multiconfiguration Calculations of Transition Data Involving Rydberg Series

Coulomb (Velocity) Gauge Recommended in Multiconfiguration Calculations of Transition Data Involving Rydberg Series

Energy Levels and Transition Parameters in Ce6+ from MCDHF Model

Mass-Difference Measurements on Heavy Nuclides with an eV/c2 Accuracy in the PENTATRAP Spectrometer

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