Isotope shift calculations of Li-like neutron-rich and neutron-deficient Mg isotopes

2017 ◽  
Vol 31 (02) ◽  
pp. 1750003
Author(s):  
Geng-Hua Yu ◽  
Peng-Yi Zhao ◽  
Bing-Ming Xu ◽  
Xiao-Ling Zhu ◽  
Wei Yang
Keyword(s):  
Isotope Shift ◽  
Nuclear Charge ◽  
Magnesium Isotopes ◽  
Isotope Shifts ◽  
Charge Radii ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
Mg Isotopes ◽  
Interaction Approach ◽  
Relativistic Configuration Interaction

The isotope shifts of the [Formula: see text]–[Formula: see text] transitions for the Li-like neutron-rich and neutron-deficient [Formula: see text] isotopes are calculated using the multi-configuration Dirac–Hartree–Fock (MCDHF) method and the relativistic configuration interaction approach. The results provided herein can be employed for the consistency check with the nuclear root-mean-square (rms) nuclear charge radii of the short-lived magnesium isotopes from the experimental isotope shifts using the corresponding transitions. The methods used here could also be applied to other few-electron Li-like systems and the analogous isotope shift results could be obtained.

scholarly journals Theoretical investigation of energy levels and transition data for S II, Cl III, Ar IV

2019 ◽  
Vol 623 ◽  
pp. A155 ◽  
Author(s):  
P. Rynkun ◽  
G. Gaigalas ◽  
P. Jönsson
Keyword(s):  
Energy Levels ◽  
Electric Quadrupole ◽  
General Purpose ◽  
Energy Spectra ◽  
Astrophysical Plasmas ◽  
Internal Validation ◽  
Hartree Fock ◽  
Self Energy ◽  
Relativistic Configuration ◽  
Relativistic Configuration Interaction

Aims. The aim of this work is to present accurate and extensive results of energy spectra and transition data for the S II, Cl III, and Ar IV ions. These data are useful for understanding and probing physical processes and conditions in various types of astrophysical plasmas.Methods. The multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction (RCI) methods, which are implemented in the general-purpose relativistic atomic structure package GRASP2K, are used in the present work. In the RCI calculations the transverse-photon (Breit) interaction, the vacuum polarization, and the self-energy corrections are included.Results. Energy spectra are presented comprising the 134, 87, and 103 lowest states in S II, Cl III, and Ar IV, respectively. Energy levels are in very good agreement with NIST database recommended values and associated with smaller uncertainties than energies from other theoretical computations. Electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2) transition data are computed between the above states together with the corresponding lifetimes. Based on internal validation, transition rates for the majority of the stronger transitions are estimated to have uncertainties of less than 3%.

scholarly journals Extended transition rates and lifetimes in Al I and Al II from systematic multiconfiguration calculations

2018 ◽  
Vol 621 ◽  
pp. A16 ◽  
Author(s):  
A. Papoulia ◽  
J. Ekman ◽  
P. Jönsson
Keyword(s):  
Infrared Region ◽  
Atomic Data ◽  
State Function ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Nist Database ◽  
Relativistic Configuration ◽  
Electron Correlation Effects ◽  
Relativistic Configuration Interaction ◽  
New Generation

MultiConfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) calculations were performed for 28 and 78 states in neutral and singly ionized aluminium, respectively. In Al I, the configurations of interest are 3s2nl for n = 3, 4, 5 with l = 0 to 4, as well as 3s3p2 and 3s26l for l = 0, 1, 2. In Al II, in addition to the ground configuration 3s2, the studied configurations are 3snl with n = 3 to 6 and l = 0 to 5, 3p2, 3s7s, 3s7p, and 3p3d. Valence and core-valence electron correlation effects are systematically accounted for through large configuration state function (CSF) expansions. Calculated excitation energies are found to be in excellent agreement with experimental data from the National Institute of Standards and Technology (NIST) database. Lifetimes and transition data for radiative electric dipole (E1) transitions are given and compared with results from previous calculations and available measurements for both Al I and Al II. The computed lifetimes of Al I are in very good agreement with the measured lifetimes in high-precision laser spectroscopy experiments. The present calculations provide a substantial amount of updated atomic data, including transition data in the infrared region. This is particularly important since the new generation of telescopes are designed for this region. There is a significant improvement in accuracy, in particular for the more complex system of neutral Al I. The complete tables of transition data are available at the CDS.

scholarly journals Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination

2011 ◽  
Vol 83 (1) ◽  
Author(s):  
W. Nörtershäuser ◽  
R. Sánchez ◽  
G. Ewald ◽  
A. Dax ◽  
J. Behr ◽  
...  
Keyword(s):  
Isotope Shift ◽  
Nuclear Charge ◽  
Lithium Isotopes ◽  
Charge Radii

Benchmarking Multiconfiguration Dirac–Hartree–Fock Calculations for Astrophysics: Si-like Ions from Cr xi to Zn xvii

2021 ◽  
Vol 257 (2) ◽  
pp. 56
Author(s):  
X. H. Zhang ◽  
G. Del Zanna ◽  
K. Wang ◽  
P. Rynkun ◽  
P. Jönsson ◽  
...  
Keyword(s):  
Line Strength ◽  
Estimation Method ◽  
Radiative Transition ◽  
Atomic Data ◽  
Excitation Energies ◽  
Data Set ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
Experimental Values ◽  
Relativistic Configuration Interaction

Abstract The multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction methods are used to provide excitation energies, lifetimes, and radiative transition data for the 604 (699, 702, 704, 704, 704, and 699) lowest levels of the 3s 23p 2, 3s3p 3, 3s 23p3d, 3p 4, 3s3p 23d, 3s 23d 2, 3p 33d, 3s3p3d 2, 3s3d 3, 3p3d 3, 3p 23d 2, 3s 23p4s, 3s 23p4p, 3s 23p4d, 3s 23p4f, 3s3p 24s, 3s3p 24p, 3s3p 24d, 3s3p 24f, 3s 23d4s, 3s 23d4p, 3p 34s, 3p 34p, 3s3p3d4s, 3s 23p5s, and 3s 23p5p configurations in Cr xi, (Mn xii, Fe xiii, Co xiv, Ni xv, Cu xvi, and Zn xvii). Previous line identifications of Fe xiii and Ni xv in the EUV and X-ray wavelength ranges are reviewed by comprehensively comparing the MCDHF theoretical results with available experimental data. Many recent identifications of Fe xiii and Ni xv lines are confirmed, and several new identifications for these two ions are proposed. A consistent atomic data set with spectroscopic accuracy is provided for the lowest hundreds of levels for Si-like ions of iron-group elements of astrophysical interest, for which experimental values are scarce. The uncertainty estimation method suggested by Kramida, applied to the comparison of the length and velocity line strength values, is used for ranking the transition data. The correlation of the latter with the gauge dependency patterns of the line strengths is investigated.

Changes in mean-square nuclear charge radii from optical isotope shifts

1987 ◽  
Vol 37 (3) ◽  
pp. 455-490 ◽  
Author(s):  
P. Aufmuth ◽  
K. Heilig ◽  
A. Steudel
Keyword(s):  
Nuclear Charge ◽  
Mean Square ◽  
Isotope Shifts ◽  
Charge Radii

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

Atoms ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 106 ◽  
Author(s):  
Asimina Papoulia ◽  
Jörgen Ekman ◽  
Gediminas Gaigalas ◽  
Michel Godefroid ◽  
Stefan Gustafsson ◽  
...  
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Wavelength Region ◽  
Theoretical Data ◽  
Rydberg Series ◽  
Atomic Systems ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
Atomic States ◽  
Relativistic Configuration Interaction

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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