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1. Large shape staggering in neutron-deficient Bi isotopes

Author

A.V. Oleynichenko, Julian C. Berengut, Mark Bissell, Jean-Pierre Dognon, K. Chrysalidis, R. F. Garcia Ruiz, V. N. Fedosseev, B. Andel, Sacha Schiffmann, V. Panteleev, C. Raison, B. A. Marsh, C. Seiffert, G. J. Farooq-Smith, Magdalena Elantkowska, D. V. Fedorov, J. Karls, Thomas Elias Cocolios, Ephraim Eliav, Andréi Zaitsevskii, Sebastian Rothe, M. D. Seliverstov, Dominik Studer, M. Huyse, M. Al Monthery, Kara Marie Lynch, P. Mosat, K. Rezynkina, P. Van Duppen, P. Molkanov, L. V. Skripnikov, M. L. Reitsma, Ralf Erik Rossel, A. Barzakh, M. Stryjczyk, S. Péru, S. Sels, S. Hilaire, C. Granados, R. D. Harding, P. Larmonier, R. Heinke, J. G. Li (李冀光), S. Goriely, Anastasia Borschevsky, L. P. Gaffney, Jacek Bieron, Andrei Andreyev, T. Day Goodacre, Jarosław Ruczkowski, Michel Godefroid, M. Verlinde, Sebastian Wilman, S. Antalic, D. E. Maison, J. G. Cubiss, Pekka Pyykkö, National Research Centre 'Kurchatov Institute': Petersburg Nuclear Physics Institute, Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom, Advanced Science Research Center and Nuclear Science Research Institute, Japan Atomic Energy Agency, Japan Atomic Energy Agency, Instituut voor Kern- en Stralingsfysica (K.U. LEUVEN), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Laboratoire Matière sous Conditions Extrêmes (LMCE), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Department of Nuclear Physics and Biophysics, Comenius University in Bratislava, School of Physics, University of New South Wales [Canberra Campus] (UNSW), Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, School of Physics and Astronomy [Manchester], University of Manchester [Manchester], Van Swinderen Institute, University of Groningen [Groningen], European Organization for Nuclear Research (CERN), Institut für Physik Johannes Gutenberg Universität, Johannes Gutenberg - Universität Mainz (JGU), TRIUMF [Vancouver], Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Poznan University of Technology (PUT), School of Chemistry, Tel Aviv University [Tel Aviv], School of Computing and Engineering [London] (https://www.uwl.ac.uk/academic-schools/computing), University of West London, Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), CERC - Centre d'Études et de Recherches Comparatistes - EA 172 (CERC), Université Sorbonne Nouvelle - Paris 3, Department of Physics [Gothenburg], University of Gothenburg (GU), Institute of Applied Physics and Computational Mathematics [Beijing] (IAPCM), China Academy of Engineering Physics (CAEP), Saint Petersburg State University (SPBU), Department of Chemistry, Lomonosov Moscow State University, Lomonosov Moscow State University (MSU), Department of Chemistry [Helsinki], Falculty of Science [Helsinki], University of Helsinki-University of Helsinki, University of Jyväskylä (JYU), National Natural Science Foundation of China under Grant No. 11874090, Fonds de la Recherche Scientifique (F. R. S.-FNRS) and the Fonds Wetenschappelijk Onderzoek-Vlaanderen (FWO) under the EOS Project No. O022818F, by GOA/2015/010 (BOF KU Leuven), U.K. Science and Technology Facilities Council, Slovak Research and Development Agency (Contract No. APVV-18-0268), the Slovak grant agency VEGA (Contract No. 1/0651/21), RFBR according to the research projects N 19-02-00005 and N 20-32-70177, the Russian Science Foundation (Grant No. 19-72-10019), The foundation for the advancement of theoretical physics and mathematics 'BASIS' grant according to Projects No. 21-1-2-47-1 and No. 20-1-5-76-1, European Project: 771036,MAIDEN, European Project: 654002,H2020,H2020-INFRAIA-2014-2015,ENSAR2(2016), Comenius University in Bratislava, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Tel Aviv University (TAU), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Precision Frontier, and Department of Chemistry

Subjects
Physics, Magnetic moment, 010308 nuclear & particles physics, 116 Chemical sciences, General Physics and Astronomy, [CHIM.MATE]Chemical Sciences/Material chemistry, 01 natural sciences, Physique atomique et nucléaire, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Charge radius, Neutron number, 0103 physical sciences, Quadrupole, Nuclear Physics - Experiment, Neutron, Atomic physics, 010306 general physics, Spin (physics), Ground state, Magnetic dipole
Abstract

The changes in the mean-square charge radius (relative to 209Bi), magnetic dipole, and electric quadrupole moments of 187,188,189,191Bi were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in 187,188,189Big, manifested by a sharp radius increase for the ground state of 188Bi relative to the neighboring 187,189Big. A large isomer shift was also observed for 188Bim. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were identified by the blocked quasiparticle configuration compatible with the observed spin, parity, and magnetic moment. ispartof: Physical Review Letters vol:127 issue:9 ispartof: location:United States status: published

Published
2021
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2. Ab initio multiconfiguration Dirac-Hartree-Fock calculations of the In and Tl electron affinities and their isotope shifts

Author

Sacha Schiffmann, Michel Godefroid, Ran Si, Kai Wang, and Chong Yang Chen

Subjects
Physics, Excited state, Metastability, Bound state, Ab initio, Hartree–Fock method, Atomic physics, Configuration interaction, Ground state, Energy (signal processing)
Abstract

We report multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations on the thallium (Tl) electron affinity, as well as on the excited energy levels arising from the ground configuration of ${\mathrm{Tl}}^{\ensuremath{-}}$. The results are compared with the available experimental values and further validated by extending the study to its homologous, lighter element, indium (In), belonging to group 13 (III.A) of the Periodic Table. The calculated electron affinities of In and Tl, 383.4 and 322.8 meV, agree with the latest measurements by within 1%. Three bound states ${}^{3}{P}_{0,1,2}$ are confirmed in the $5{s}^{2}5{p}^{2}$ configuration of ${\mathrm{In}}^{\ensuremath{-}}$, while only the ground state ${}^{3}{P}_{0}$ is bound in the $6{s}^{2}6{p}^{2}$ configuration of ${\mathrm{Tl}}^{\ensuremath{-}}$. The isotope shifts on the In and Tl electron affinities are also estimated. The E2 and M1 intraconfiguration radiative transition rates within $5{s}^{2}5{p}^{2} {}^{3}{P}_{0,1,2}$ of ${\mathrm{In}}^{\ensuremath{-}}$ are used to calculate the radiative lifetimes of the metastable ${}^{3}{P}_{1,2}$ levels.

Published
2021
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3. Ab initio electronic factors of the A and B hyperfine structure constants for the 5s25p6sP1o1,3 states in Sn i

Author

Pekka Pyykkö, Per Jönsson, Michel Godefroid, Zoltán Harman, Gediminas Gaigalas, Sacha Schiffmann, Jacek Bieron, Natalia S. Oreshkina, I. I. Tupitsyn, and Asimina Papoulia

Subjects
Physics, Electronic correlation, Q value, Ab initio, Configuration interaction, 01 natural sciences, 010305 fluids & plasmas, Ab initio quantum chemistry methods, Excited state, 0103 physical sciences, Quadrupole, Physics::Atomic Physics, Atomic physics, 010306 general physics, Hyperfine structure
Abstract

Large-scale ab initio calculations of the electronic contribution to the electric quadrupole hyperfine constant B were performed for the 5s25p6s1,3Po1 excited states of neutral tin. To probe the sensitivity of B to different electron correlation effects, three sets of variational multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations employing different strategies were carried out. In addition, a fourth set of calculations was based on the configuration interaction Dirac-Fock-Sturm theory. For the 5s25p6s 1Po1 state, the final value of B/Q=703(50) MHz/b differs by 0.4% from the one recently used by Yordanov et al. [Commun. Phys. 3, 107 (2020)] to extract the nuclear quadrupole moments Q for tin isotopes in the range 117−131Sn from collinear laser spectroscopy measurements. Efforts were made to provide a realistic theoretical uncertainty for the final B/Q value of the 5s25p6s 1Po1 state based on statistical principles and on correlation with the electronic contribution to the magnetic dipole hyperfine constant A.

Published
2021
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4. Experimental and theoretical studies of excited states in Ir

Author

M. K. Kristiansson, Jon Grumer, J. Karls, Dag Hanstorp, Henning Zettergren, Henning T. Schmidt, Gustav Eklund, V. Ideböhn, N. D. Gibson, Tomas Brage, Sacha Schiffmann, and N. de Ruette

Subjects
Physics, Excited state, Atom and Molecular Physics and Optics, Binding energy, Bound state, Relaxation (NMR), Ionic bonding, Order (ring theory), Généralités, Atom- och molekylfysik och optik, Ideal (ring theory), Atomic physics, Ion
Abstract

The properties of atomic negative ions are to a large extent determined by electron-electron correlation which makes them an ideal testing ground for atomic many-body physics. In this paper, we present a detailed experimental and theoretical study of excited states in the negative ion of iridium. The ions were stored at cryogenic temperatures using the double electrostatic ion ring experiment facility at Stockholm University. Laser photodetachment was used to monitor the relaxation of three bound excited states belonging to the [Xe] 4f145d86s2 ionic ground configuration. Our measurements show that the first excited state has a lifetime much longer than the ion-beam storage time of 1230±100s. The binding energy of this state was measured to be 1.045±0.002eV. The lifetimes of the second and third excited states were experimentally determined to be 133±10 and 172±35ms, respectively. Multiconfiguration Dirac-Hartree-Fock calculations were performed in order to extract binding energies and lifetimes. These calculations predict the existence of the third excited bound state that was detected experimentally. The computed lifetimes for the three excited bound states agree well with the experimental results and allow for a clear identification of the detected levels., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2021

5. Structural trends in atomic nuclei from laser spectroscopy of tin

Author

Stefan E. Schmidt, Zhengyu Xu, Gerda Neyens, A. Kanellakopoulos, Witold Nazarewicz, S. Kaufmann, Mark Bissell, Sacha Schiffmann, L. Wehner, B. Maaß, W. Gins, Per Jönsson, Bradley Cheal, S. Malbrunot-Ettenauer, Jörgen Ekman, Zoltán Harman, Rodolfo Sánchez, Christoph H. Keitel, Natalia S. Oreshkina, L. V. Rodríguez, Paul-Gerhard Reinhard, Klaus Blaum, Jacek Bieron, Michel Godefroid, L. Xie, Christian Gorges, Rainer Neugart, Asimina Papoulia, Pekka Pyykkö, Wilfried Nörtershäuser, Gediminas Gaigalas, Xiaofei Yang, Ronald Fernando Garcia Ruiz, Dimiter L. Balabanski, Stefan Sailer, S. Lechner, V. Lagaki, Georgi Georgiev, H. Heylen, Deyan T. Yordanov, C. Wraith, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Balabanski, DL, Bieroń, J, Bissell, ML, Blaum, K, Cheal, B, Ekman, J, Gaigalas, G, Garcia Ruiz, RF, Georgiev, G, Gins, W, Godefroid, MR, Gorges, C, Harman, Z, Heylen, H, Jönsson, P, Kanellakopoulos, Anastasios, Kaufmann, S, Keitel, CH, Lagaki, V, Lechner, S, Maaß, B, Malbrunot-Ettenauer, S, Nazarewicz, W, Neugart, R, Neyens, G, Nörtershäuser, W, Oreshkina, NS, Papoulia, A, Pyykkö, P, Reinhard, P-G, Sailer, S, Sánchez, R, Schiffmann, S, Schmidt, S, Wehner, L, Wraith, C, Xie, L, Xu, ZY, Yang, XF, Department of Chemistry, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
CHARGE RADII, Materials science, Proton, Atom and Molecular Physics and Optics, Research group Z. Harman – Division C. H. Keitel, 116 Chemical sciences, Nuclear Theory, Electron shell, General Physics and Astronomy, chemistry.chemical_element, lcsh:Astrophysics, Atomic structure calculations, nuclear structure calculations, the neutral atom of Sn, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 114 Physical sciences, Effective nuclear charge, 0103 physical sciences, Isotopes of tin, lcsh:QB460-466, ISOTOPE SHIFT, ELEMENTS, ddc:530, Physics::Atomic Physics, 010306 general physics, Spectroscopy, Nuclear Experiment, Hyperfine structure, 010308 nuclear & particles physics, lcsh:QC1-999, 3. Good health, QUADRUPOLE-MOMENTS, chemistry, GAS, Atomic nucleus, Physics::Accelerator Physics, Atom- och molekylfysik och optik, Atomic physics, Präzisionsexperimente - Abteilung Blaum, Tin, lcsh:Physics
Abstract

Communications Physics 3(1), 107 (2020). doi:10.1038/s42005-020-0348-9, Published by Springer Nature, London

Published
2020
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6. In-gas-cell laser resonance ionization spectroscopy of Ir196,197,198

Author

Hirofumi Watanabe, Michiharu Wada, Hironobu Ishiyama, Hideki Ueno, Sacha Schiffmann, Jörgen Ekman, Jun Young Moon, Yoshikazu Hirayama, Y. X. Watanabe, A. Ozawa, S. Kanaya, M. Mukai, M. Oyaizu, Y. Kakiguchi, J. H. Park, Peter Schury, Satoshi Kimura, M. Ahmed, S. C. Jeong, Hiroari Miyatake, and Michel Godefroid

Subjects
Physics, 010308 nuclear & particles physics, Charge (physics), 01 natural sciences, Spectral line, Ionization, 0103 physical sciences, Quadrupole, Physics::Atomic Physics, Atomic physics, 010306 general physics, Spin (physics), Spectroscopy, Magnetic dipole, Hyperfine structure
Abstract

Hyperfine structure (HFS) measurements of neutron-rich iridium isotopes $^{196,197,198}\mathrm{Ir}$ ($Z=77,\phantom{\rule{0.16em}{0ex}}N=119$--121) were performed via in-gas-cell laser resonance ionization spectroscopy at the KEK Isotope Separation System. Magnetic dipole moments $\ensuremath{\mu}$ and isotope shifts were determined from the HFS spectra. The variation of mean-square charge radii and quadrupole deformation parameters of these isotopes were evaluated from the isotope shifts. The $\ensuremath{\mu}$ value of $^{197}\mathrm{Ir}$ agreed with a theoretical value based on the strong coupling model, and the Ir nucleus was interpreted as prolately deformed by the theoretical calculations. The $\ensuremath{\mu}$ values of $^{196,198}\mathrm{Ir}$ were also compared with semiempirical values calculated based on the strong coupling model. From the comparison, we can suggest the possible spin values of ${I}^{\ensuremath{\pi}}=1,{2}^{\ensuremath{-}}$ for $^{196}\mathrm{Ir}$ and ${I}^{\ensuremath{\pi}}={1}^{\ensuremath{-}}$ for $^{198}\mathrm{Ir}$.

Published
2020
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7. Electronic isotope shift factors for the Ir 5d76s24F9/2→(odd,J=9/2) line at 247.587 nm

Author

Michel Godefroid and Sacha Schiffmann

Subjects
Mean square, Physics, Radiation, 010504 meteorology & atmospheric sciences, Isotope, Nuclear Theory, Phase (waves), chemistry.chemical_element, Configuration interaction, Tracking (particle physics), 01 natural sciences, Atomic and Molecular Physics, and Optics, chemistry, Theoretical chemistry, Physics::Atomic Physics, Iridium, Atomic physics, Spectroscopy, 0105 earth and related environmental sciences, Line (formation)
Abstract

We present the theoretical calculations of the electronic isotope shift factors of the 5 d 7 6 s 2 4 F 9 / 2 → ( odd , J = 9 / 2 ) line at 247.587 nm, that were recently used to extract nuclear mean square radii and nuclear deformations of iridium isotopes [Mukai et al. (2020)]. The fully relativistic multiconfiguration Dirac-Hartree-Fock method and the relativistic configuration interaction method were used to perform the atomic structure calculations. Additional properties such as the sharing rule, Lande g factors or phase tracking were employed to ensure an adequate description of the targeted odd level.

Published
2021
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8. Relativistic semiempirical-core-potential calculations in Ca+,Sr+ , and Ba+ ions on Lagrange meshes

Author

Livio Filippin, Daniel Jean Baye, Michel Godefroid, Sacha Schiffmann, and Jérémy Dohet-Eraly

Subjects
Physics, Electronic correlation, Electron, 01 natural sciences, 010305 fluids & plasmas, Ion, symbols.namesake, Atomic orbital, Metastability, 0103 physical sciences, Physics::Atomic and Molecular Clusters, symbols, Gaussian quadrature, Atomic physics, 010306 general physics, Valence electron, Hamiltonian (quantum mechanics)
Abstract

Relativistic atomic structure calculations are carried out in alkaline-earth-metal ions using a semiempirical-core-potential approach. The systems are partitioned into frozen-core electrons and an active valence electron. The core orbitals are defined by a Dirac-Hartree-Fock calculation using the grasp2k package. The valence electron is described by a Dirac-like Hamiltonian involving a core-polarization potential to simulate the core-valence electron correlation. The associated equation is solved with the Lagrange-mesh method, which is an approximate variational approach having the form of a mesh calculation because of the use of a Gauss quadrature to calculate matrix elements. Properties involving the low-lying metastable $^{2}D_{3/2,5/2}$ states of ${\mathrm{Ca}}^{+}, {\mathrm{Sr}}^{+}$, and ${\mathrm{Ba}}^{+}$ are studied, such as polarizabilities, one- and two-photon decay rates, and lifetimes. Good agreement is found with other theory and observation, which is promising for further applications in alkalilike systems.

Published
2018
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9. Benchmarking Atomic Data from Large-scale Multiconfiguration Dirac–Hartree–Fock Calculations for Astrophysics: S-like Ions from Cr ix to Cu xiv

Author

G. Del Zanna, Ran Si, Michel Godefroid, Sacha Schiffmann, Gediminas Gaigalas, C. X. Song, Per Jönsson, Chong Yang Chen, X. H. Zhao, Kai Wang, and Jun Yan

Subjects
Physics, 010504 meteorology & atmospheric sciences, Dirac (software), atomic processes, Hartree–Fock method, Astronomy and Astrophysics, Scale (descriptive set theory), Astronomie, 01 natural sciences, Sciences de l'espace, Ion, Space and Planetary Science, 0103 physical sciences, atomic data, Radiative transition, Atomic physics, 010303 astronomy & astrophysics, Astrophysique, 0105 earth and related environmental sciences, Atomic data
Abstract

We present a consistent set of calculated energies and E1, M1, E2, M2 radiative transition data for the main n = 3 levels from the 3s 23p 4, 3p 6, 3p6, 3s3p43d, 3s23p23d2, 3s3p5, 3s23p33d, and 3s3p33d2 configurations for S-like ions from Cr ix to Cu xiv. The fully relativistic multiconfiguration Dirac-Hartree-Fock method implemented in the GRASP2K code is used to perform the present calculations. The excitation energies of the lowest 47 levels from the ,and configurations, producing the strongest lines, are found to be in good agreement, reaching spectroscopic accuracy, with the latest experimental values for Fe xi evaluated by Del Zanna. Our energies can reliably be used to identify in astrophysical and laboratory spectra the levels in other S-like ions, which are mostly unknown. On the contrary, significant discrepancies with the 3s3p 43d levels were found, emphasizing the need for more detailed experimental studies. A few new tentative identifications are suggested. The benchmarks we present indicate that our consistent set of radiative data is accurate and can be used for spectral line modeling., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2018
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