Extended Calculations of Energy Levels and Transition Rates for Singly Ionized Lanthanide Elements. II. Tb−Yb

2021 ◽  
Vol 257 (2) ◽  
pp. 29
Author(s):  
Laima Radžiūtė ◽  
Gediminas Gaigalas ◽  
Daiji Kato ◽  
Pavel Rynkun ◽  
Masaomi Tanaka
Keyword(s):  
Large Scale ◽  
Transition Probabilities ◽  
Energy Levels ◽  
General Purpose ◽  
Hartree Fock ◽  
Lanthanide Elements ◽  
Average Accuracy ◽  
Nist Database ◽  
Relativistic Configuration ◽  
Relativistic Configuration Interaction

Abstract In this work, we continue large-scale ab initio computations for single ionized lanthanides. Extended atomic calculations for the set of ions from Pr ii (Z = 59) to Gd ii (Z = 64) have been performed in our previous work. In this study, ions from Tb ii (Z = 65) to Yb ii (Z = 70) are analyzed. By employing the same multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction methods that are implemented in the general-purpose relativistic atomic structure package GRASP2018, the energy levels and transition data of electric dipole (E1) transitions are computed. These computations are based on the strategies (with small variations) of Paper I. Accuracy of data is evaluated by comparing the computed energy levels with the data provided by the National Institute of Standards and Technology (NIST) database and with data from various methods. We obtain the average accuracy in the energy level compared with the NIST database: 6%, 5%, 4%, 5%, 3%, and 3% for Tb ii, Dy ii, Ho ii, Er ii, Tm ii, and Yb ii, respectively. We also provide extensive comparison of transition probabilities and wavelengths. Our results reach the average accuracy of transition wavelengths: 9%, 9%, 9%, 3%, 4%, and 11% for Tb ii, Dy ii, Ho ii, Er ii, Tm ii, and Yb ii, respectively.

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 MCDHF and RCI calculations of energy levels, lifetimes, and transition rates in Si III and Si IV

2019 ◽  
Vol 631 ◽  
pp. A29 ◽  
Author(s):  
B. Atalay ◽  
T. Brage ◽  
P. Jönsson ◽  
H. Hartman
Keyword(s):  
Energy Levels ◽  
Rydberg Series ◽  
Excitation Energies ◽  
Plasma Properties ◽  
Hartree Fock ◽  
Nist Database ◽  
Relativistic Configuration ◽  
Important Extension ◽  
Relativistic Configuration Interaction

We present extensive multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations including 106 states in doubly ionized silicon (Si III) and 45 states in triply ionized silicon (Si IV), which are important for astrophysical determination of plasma properties in different objects. These calculations represents an important extension and improvement of earlier calculations especially for Si III. The calculations are in good agreement with available experiments for excitation energies, transition properties, and lifetimes. Important deviations from the NIST-database for a selection of perturbed Rydberg series are discussed in detail.

scholarly journals Fine-structure energy levels and radiative rates in Al-like molybdenum

2017 ◽  
Vol 95 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Meifei Mao
Keyword(s):  
Configuration Interaction ◽  
Quantum Electrodynamics ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Ground Level ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
Relativistic Configuration Interaction ◽  
Configuration Interaction Calculations ◽  
Good Agreement

Based on relativistic wavefunctions from multiconfigurational Dirac–Hartree–Fock and configuration interaction calculations, energy levels, radiative rates, and wavelengths are evaluated for all levels of 3s23p, 3s3p2, 3s23d, 3p3, 3s3p3d, 3p23d, and 3s3d2 configurations of Al-like molybdenum ion (Mo XXX). Transition probabilities are reported for E1 and M2 transitions from the ground level. The valence–valence and core–valence correlation effects are accounted for in a systematic way. Breit interactions and quantum electrodynamics effects are estimated in subsequent relativistic configuration interaction calculations. Comparisons are made with the available data in the literature and good agreement has been found, which confirms the reliability of our results.

scholarly journals Theoretical investigation of energy levels and transition data for P II

2019 ◽  
Vol 622 ◽  
pp. A167 ◽  
Author(s):  
P. Rynkun ◽  
L. Radžiūtė ◽  
G. Gaigalas ◽  
P. Jönsson
Keyword(s):  
Energy Levels ◽  
General Purpose ◽  
Transition Energies ◽  
Hartree Fock ◽  
Self Energy ◽  
Relativistic Configuration ◽  
Transverse Photon ◽  
Experimental Values ◽  
Relativistic Configuration Interaction ◽  
Average Uncertainty

Aims. The main goal of this paper is to present accurate and extensive transition data for the P II ion. These data are useful in various astrophysical applications. 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, were used in the present work. In the RCI calculations the transverse-photon (Breit) interaction, the vacuum polarization, and the self-energy corrections were included. Results. Energy spectra are presented for 48 even states of the 3s23p2, 3s23p{4p, 4f, 5p, 5f, 6p}, 3s3p23d configurations, and for 58 odd states of the 3s3p3, 3s23p{3d, 4s, 4d, 5s, 5d, 6s} configurations in the P II ion. Electric dipole (E1) transition data are computed between these states along with the corresponding lifetimes. The average uncertainty of the computed transition energies is between five and ten times smaller than the uncertainties from previous calculations. The computed lifetimes for the 3s23p4s3Po states are within the error bars of the most current experimental values.

scholarly journals Extended theoretical transition data in C i–iv

2021 ◽  
Vol 502 (3) ◽  
pp. 3780-3799
Author(s):  
W Li ◽  
A M Amarsi ◽  
A Papoulia ◽  
J Ekman ◽  
P Jönsson
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Internal Validation ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
The Difference ◽  
The One ◽  
Relative Differences

ABSTRACT Accurate atomic data are essential for opacity calculations and for abundance analyses of the Sun and other stars. The aim of this work is to provide accurate and extensive results of energy levels and transition data for C i–iv. The Multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction methods were used in this work. To improve the quality of the wavefunctions and reduce the relative differences between length and velocity forms for transition data involving high Rydberg states, alternative computational strategies were employed by imposing restrictions on the electron substitutions when constructing the orbital basis for each atom and ion. Transition data, for example, weighted oscillator strengths and transition probabilities, are given for radiative electric dipole (E1) transitions involving levels up to 1s22s22p6s for C i, up to 1s22s27f for C ii, up to 1s22s7f for C iii, and up to 1s28g for C iv. Using the difference between the transition rates in length and velocity gauges as an internal validation, the average uncertainties of all presented E1 transitions are estimated to be 8.05 per cent, 7.20 per cent, 1.77 per cent, and 0.28 per cent, respectively, for C i–iv. Extensive comparisons with available experimental and theoretical results are performed and good agreement is observed for most of the transitions. In addition, the C i data were employed in a re-analysis of the solar carbon abundance. The new transition data give a line-by-line dispersion similar to the one obtained when using transition data that are typically used in stellar spectroscopic applications today.

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 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.

scholarly journals Theoretical investigation of oscillator strengths and lifetimes in Ti II

2020 ◽  
Vol 643 ◽  
pp. A156
Author(s):  
W. Li ◽  
H. Hartman ◽  
K. Wang ◽  
P. Jönsson
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Electric Quadrupole ◽  
General Purpose ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Self Energy ◽  
Theoretical Predictions

Aims. Accurate atomic data for Ti II are essential for abundance analyses in astronomical objects. The aim of this work is to provide accurate and extensive results of oscillator strengths and lifetimes for Ti II. Methods. The multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction (RCI) methods, which are implemented in the general-purpose relativistic atomic structure package GRASP2018, were used in the present work. In the final RCI calculations, the transverse-photon (Breit) interaction, the vacuum polarisation, and the self-energy corrections were included. Results. Energy levels and transition data were calculated for the 99 lowest states in Ti II. Calculated excitation energies are found to be in good agreement with experimental data from the Atomic Spectra Database of the National Institute of Standards and Technology based on the study by Huldt et al. Lifetimes and transition data, for example, line strengths, weighted oscillator strengths, and transition probabilities for radiative electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2) transitions, are given and extensively compared with the results from previous calculations and measurements, when available. The present theoretical results of the oscillator strengths are, overall, in better agreement with values from the experiments than the other theoretical predictions. The computed lifetimes of the odd states are in excellent agreement with the measured lifetimes. Finally, we suggest a relabelling of the 3d2(12D)4p y2 D3/2o and z2 P3/2o levels.

Multiconfiguration Dirac-Fock results for forbidden transitions in the 2p 4 configuration

Open Physics ◽  
2011 ◽  
Vol 9 (5) ◽  
Author(s):  
Feng Hu ◽  
Jiamin Yang ◽  
Chuanke Wang ◽  
Gang Jiang ◽  
Xuefeng Zhao ◽  
...  
Keyword(s):  
Quantum Electrodynamics ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Electric Quadrupole ◽  
Optimal Level ◽  
Forbidden Transition ◽  
Relativistic Configuration ◽  
Relativistic Configuration Interaction ◽  
Configuration Interaction Calculations ◽  
State Configuration

AbstractRelativistic configuration interaction calculations with the inclusion of the Breit interaction, quantum electrodynamics and finite nuclear mass corrections have been carried out in the extended optimal level scheme using multiconfiguration Dirac-Fock wavefunctions on the forbidden transition probabilities for the 2p 4 ground state configuration of the oxygen isoelectronic sequence for 8 ⩽ Z ⩽ 42. Electric quadrupole and magnetic dipole transition probabilities are reported for transitions between several of these levels. Our results are compared with those from other theories and experiments. Our energy levels are in better agreement with experiment than other theories.

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