A5051580375- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Nuclear physics research studies
- Mass Spectrometry Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Gamma-ray bursts and supernovae
- Laser-induced spectroscopy and plasma
- Astro and Planetary Science
- Electron and X-Ray Spectroscopy Techniques
- Solid-state spectroscopy and crystallography
- Cold Atom Physics and Bose-Einstein Condensates
- Inorganic Fluorides and Related Compounds
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Advanced Frequency and Time Standards
- Advanced Physical and Chemical Molecular Interactions
- Astronomical Observations and Instrumentation
- Rare-earth and actinide compounds
- Advanced NMR Techniques and Applications
- Particle accelerators and beam dynamics
- Scientific Research and Discoveries
- Crystal Structures and Properties
- Atomic and Subatomic Physics Research
- Radioactive element chemistry and processing
- Inorganic Chemistry and Materials
Institute of Theoretical Physics
2018-2025
Vilnius University
2016-2025
Gdańsk University of Technology
2019
National Institute of Standards and Technology
2006-2016
National Institute for Fusion Science
2014-2015
Lithuanian University of Educational Sciences
2012-2013
Malmö University
2013
Pedagogical University
2005-2012
Université Libre de Bruxelles
2012
Vilnius University of Applied Sciences
2004-2010
Multiconfiguration wave function expansions combined with configuration interaction methods are a method of choice for complex atoms where atomic state functions expanded in basis functions. Combined variational such as the multiconfiguration Hartree–Fock (MCHF) or Dirac–Hartree–Fock (MCDHF), associated set radial can be optimized levels interest. The present review updates MCHF theory to include MCDHF, describes multireference single and double process generating systematic procedure...
Coalescence of neutron stars gives rise to kilonova, thermal emission powered by radioactive decays freshly synthesized r-process nuclei. Although observational properties are largely affected bound-bound opacities elements, available atomic data have been limited. In this paper, we study element-to-element variation the in ejecta star mergers performing systematic structure calculations elements for first time. We show that distributions energy levels tend be higher as electron occupation...
In this Letter, we present mass-ratio measurements on highly charged <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mi>Yb</a:mi></a:mrow><a:mrow><a:mn>42</a:mn><a:mo>+</a:mo></a:mrow></a:msup></a:mrow></a:math> ions with a precision of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mn>4</c:mn><c:mo>×</c:mo><c:msup><c:mn>10</c:mn><c:mrow><c:mo>−</c:mo><c:mn>12</c:mn></c:mrow></c:msup></c:math> and isotope-shift...
Abstract Ejected material from neutron star mergers gives rise to electromagnetic emission powered by radioactive decays of r -process nuclei, the so-called kilonova or macronova. While properties are largely affected opacities in ejected material, available atomic data for elements still limited. We perform structure calculations elements: Se ( Z = 34), Ru 44), Te 52), Ba 56), Nd 60), and Er 68). confirm that bound–bound transitions open f -shell, lanthanide (Nd Er) higher than those other...
The JJ2LSJ program, which is important not only for the GRASP2K package but atom theory in general, presented. program performs transformation of atomic state functions(ASFs) from a jj-coupled CSF basis into an LSJ-coupled basis. In addition, implements procedure that assigns unique label to all energy levels. Examples how use are given. Several cases presented where there labeling problem.
Computational atomic physics continues to play a crucial role in both increasing the understanding of fundamental (e.g., quantum electrodynamics and correlation) producing data for interpreting observations from large-scale research facilities ranging fusion reactors high-power laser systems, space-based telescopes isotope separators. A number different computational methods, each with their own strengths weaknesses, is available meet these tasks. Here, we review relativistic...
grasp is a software package in Fortran 95, adapted to run parallel under MPI, for research atomic physics. The basic premise that, given wave function, any observed property can be computed. Thus, the first step always determine function. Different properties challenge accuracy of function different ways. This distributed MIT Licence.
ABSTRACT The late-time spectra of the kilonova AT 2017gfo associated with GW170817 exhibit a strong emission line feature at $2.1\, {\rm \mu m}$. structure develops time and there is no blueshifted absorption in spectra, suggesting that this produced by electron collision excitation. We attribute to fine Tellurium (Te) III, which one most abundant elements second r-process peak. By using synthetic spectral modelling including lines solar abundance pattern beyond first peak, i.e. atomic mass...
Coalescence of binary neutron star give rise to electromagnetic emission, kilonova, powered by radioactive decays r-process nuclei. Observations kilonova associated with GW170817 provided unique opportunity study the heavy element synthesis in Universe. However, atomic data elements decipher light curves and spectral features are not fully constructed yet. In this paper, we perform extended calculations neodymium (Nd, Z=60) impact accuracies astrophysical opacities. By employing...
The nebular phase of lanthanide-rich ejecta a neutron star merger (NSM) is studied by using one-zone model, in which the atomic properties are represented single species, neodymium (Nd). Under assumption that beta-decay r-process nuclei heat and ionization source, we solve thermal balance under non-local thermodynamic equilibrium. data including energy levels, radiative transition rates, collision strengths, recombination rate coefficients, obtained structure codes, GRASP2K HULLAC. We find...
We investigate the effect of presence lanthanides (Z = 57- 71) on kilonova at t~hours after neutron star merger for first time. For this purpose, we calculate atomic structures and opacities selected lanthanides: Nd 60), Sm 62), Eu 63). consider ionization degree up to tenth (XI), applicable ejecta t ~ a few hours merger, when temperature is T 10^5 K. find that highly ionized are exceptionally high, reaching k_exp~1000 cm^2/g Eu, due dense energy levels. Using new opacity, perform radiative...
Abstract We investigate early ( t < 1 day) kilonova from a neutron star merger by deriving atomic opacities for all the elements La to Ra Z = 57–88) ionized states V–XI. The at high temperatures with open f -shells (e.g., lanthanides) are exceptionally high, reaching <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>κ</mml:mi> </mml:mrow> <mml:mi>exp</mml:mi> </mml:msub> <mml:mspace width="0.25em"/> <mml:mo>∼</mml:mo>...
A general method is described for finding algebraic expressions matrix elements of any one- and two-particle operator an arbitrary number subshells in atomic configuration, requiring neither coefficients fractional parentage nor unit tensors. It based on the combination second quantization coupled tensorial form, angular momentum theory three spaces (orbital, spin quasispin), a generalized graphical technique. The latter allows us to graphically calculate irreducible products...
ABSTRACT Infrared emission lines arising from transitions between fine structure levels of heavy elements are expected to produce kilonova nebular emission. For the in GW170817, strong at $4.5\, {\rm \mu m}$ late times was detected by Spitzer Space Telescope but no source $3.6\, m}$. This peculiar spectrum indicates that line emitters exist around and absence To model we prepare a list based on selection rules LS coupling experimentally calibrated energy NIST database. method enables...
Atomic data, such as wavelengths, spectroscopic labels, broadening parameters and transition rates, are necessary for many applications, especially in plasma diagnostics, interpreting the spectra of distant astrophysical objects. The experiment with its limited resources is unlikely to ever be able provide a complete dataset on any atomic system. Instead, bulk data must calculated. Based fundamental principles well-justified approximations, theoretical physics derives implements algorithms...
Abstract Tin is the chemical element with largest number of stable isotopes. Its complete proton shell, comparable closed electron shells in chemically inert noble gases, not a mere precursor to extended stability; since protons carry nuclear charge, their spatial arrangement also drives electromagnetism. We report high-precision measurements electromagnetic moments and isomeric differences charge radii between lowest 1/2 + , 3/2 11/2 − states 117–131 Sn, obtained by collinear laser...
The main aim of this paper is to present accurate energy levels the ground [Xe]$4f^{12}$ and first excited [Xe]$4f^{11}5d$ configurations Er$^{2+}$. level structure Er$^{2+}$ ion was computed using multiconfiguration Dirac-Hartree-Fock relativistic configuration interaction (RCI) methods, as implemented in GRASP2018 program package. Breit interaction, self-energy vacuum polarization corrections were included RCI computations. zero-first-order approach used Energy with identification $LS$...