Jon Grumer
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View article: Infrared spectral signatures of light r-process elements in kilonovae
Infrared spectral signatures of light r-process elements in kilonovae Open
A central question regarding neutron star mergers is whether they are able to produce all the r-process elements, from first to third peak. The high abundances of first-peak elements (atomic number $Z \sim 31-40$) in the solar composition …
View article: Nebular Spectra of Kilonovae with Detailed Recombination Rates. I. Light <i>r</i>-process Composition
Nebular Spectra of Kilonovae with Detailed Recombination Rates. I. Light <i>r</i>-process Composition Open
To investigate spectra of kilonovae in the nonlocal thermal equilibrium phase ( t ≳ 1 week), we perform atomic calculations for dielectronic recombination (DR) rates for the light r -process elements Se ( Z = 34), Rb ( Z = 37), Sr ( Z = 38…
View article: <i>Ab initio</i> multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr i ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Z</mml:mi> <mml:mo>=</mml:mo> <mml:mn>103</mml:mn> </mml:mrow> </mml:math> )
<i>Ab initio</i> multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr i ( ) Open
Large-scale multiconfigurational calculations are conducted on experimentally significant transitions in Lr I and its lanthanide homologue Lu I, exhibiting good agreement with recent theoretical and experimental results. A single reference…
View article: $\textit{Ab initio}$ multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr I $\left( Z=103 \right)$
$\textit{Ab initio}$ multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr I $\left( Z=103 \right)$ Open
Large-scale multiconfigurational calculations are conducted on experimentally significant transitions in Lr I and its lanthanide homologue Lu I, exhibiting good agreement with recent theoretical and experimental results. A single reference…
View article: Actinide signatures in low electron fraction kilonova ejecta
Actinide signatures in low electron fraction kilonova ejecta Open
Neutron star (NS) mergers are known to produce heavy elements through rapid neutron capture (r-process) nucleosynthesis. Actinides are expected to be created solely by the r-process in the most neutron-rich environments. Confirming if NS m…
View article: Actinide signatures in low electron fraction kilonova ejecta
Actinide signatures in low electron fraction kilonova ejecta Open
Neutron star (NS) mergers are known to produce heavy elements through rapid neutron capture (r-process) nucleosynthesis. Actinides are expected to be created solely by the r-process in the most neutron rich environments. Confirming if NS m…
View article: Precision measurements on Si-
Precision measurements on Si- Open
High-precision measurements of the electron affinities (EA) of the three stable isotopes of silicon, $^{28}$Si, $^{29}$Si and $^{30}$Si, have been performed at the cryogenic electrostatic ion-beam storage ring DESIREE. The quantum states o…
View article: Lifetimes of excited states in Rh-
Lifetimes of excited states in Rh- Open
The radiative decay of excited states of the negative ion of rhodium, Rh$^-$, has been investigated experimentally and theoretically. The experiments were conducted at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stoc…
View article: Targeted optimization in small-scale atomic structure calculations: application to Au I
Targeted optimization in small-scale atomic structure calculations: application to Au I Open
The lack of reliable atomic data can be a severe limitation in astrophysical modelling, in particular of events such as kilonovae that require information on all neutron-capture elements across a wide range of ionization stages. Notably, t…
View article: Observation of an isotope effect in state-selective mutual neutralization of lithium with hydrogen
Observation of an isotope effect in state-selective mutual neutralization of lithium with hydrogen Open
We report on mutual neutralization measurements between 7Li+ and 1H- at effective center-of-mass collision energies in the range of 100 to 350 meV. We find that final states of lithium with principal quantum number n = 3 dominate with 3s s…
View article: NLTE spectra of kilonovae
NLTE spectra of kilonovae Open
The electromagnetic transient following a binary neutron star merger is known as a kilonova (KN). Owing to rapid expansion velocities and small ejecta masses, KNe rapidly transition into the non-local thermodynamic equilibrium (NLTE) regim…
View article: NLTE Spectra of Kilonovae
NLTE Spectra of Kilonovae Open
The electromagnetic transient following a binary neutron star merger is known as a kilonova (KN). Owing to rapid expansion velocities and small ejecta masses, KNe rapidly transition into the Non-Local Thermodynamic Equilibrium (NLTE) regim…
View article: Titanium abundances in late-type stars
Titanium abundances in late-type stars Open
The linelist in the appendix was printed with log(g f ) values and energies corresponding to the previous line, and two lines belonging to Ti I were mistakenly printed in the Ti II section.Table A.1.Lines considered in the analysis, includ…
View article: GRASP Manual for Users
GRASP Manual for Users Open
grasp is a software package in Fortran 95, adapted to run in parallel under MPI, for research in atomic physics. The basic premise is that, given a wave function, any observed atomic property can be computed. Thus, the first step is always…
View article: Extended MCDHF Calculations of Energy Levels and Transition Data for N i
Extended MCDHF Calculations of Energy Levels and Transition Data for N i Open
Accurate and extensive atomic data are essential for spectroscopic analyses of stellar atmospheres and other astronomical objects. We present energy levels, lifetimes, and transition probabilities for neutral nitrogen, the sixth most abund…
View article: Extended MCDHF calculations of energy levels and transition data for N I
Extended MCDHF calculations of energy levels and transition data for N I Open
Accurate and extensive atomic data are essential for spectroscopic analyses of stellar atmospheres and other astronomical objects. We present energy levels, lifetimes, and transition probabilities for neutral nitrogen, the sixth most abund…
View article: An Introduction to Relativistic Theory as Implemented in GRASP
An Introduction to Relativistic Theory as Implemented in GRASP Open
Computational atomic physics continues to play a crucial role in both increasing the understanding of fundamental physics (e.g., quantum electrodynamics and correlation) and producing atomic data for interpreting observations from large-sc…
View article: Titanium abundances in late-type stars
Titanium abundances in late-type stars Open
Context. The titanium abundances of late-type stars are important tracers of Galactic formation history. However, abundances inferred from Ti I and Ti II lines can be in stark disagreement in very metal-poor giants. Departures from local t…
View article: NLTE effects on kilonova expansion opacities
NLTE effects on kilonova expansion opacities Open
A binary neutron star merger produces a rapidly evolving transient known as a kilonova (KN), which peaks a few days after merger. Modelling of KNe has often been approached assuming local thermodynamic equilibrium (LTE) conditions in the e…
View article: On the validity of steady-state for nebular phase kilonovae
On the validity of steady-state for nebular phase kilonovae Open
The radioactively powered transient following a binary neutron star merger, known as a kilonova (KN), is expected to enter the steady-state nebular phase a few days after merger. Steady-state holds until thermal reprocessing time-scales be…
View article: Mutual neutralisation of O<sup>+</sup> with O<sup>−</sup>: investigation of the role of metastable ions in a combined experimental and theoretical study
Mutual neutralisation of O<sup>+</sup> with O<sup>−</sup>: investigation of the role of metastable ions in a combined experimental and theoretical study Open
The mutual neutralisation of O + with O − has been studied in a double ion-beam storage ring with combined merged-beams, imaging and timing techniques.
View article: Excitation and charge transfer in low-energy hydrogen atom collisions with neutral manganese and titanium
Excitation and charge transfer in low-energy hydrogen atom collisions with neutral manganese and titanium Open
Data for inelastic processes due to hydrogen atom collisions with manganese and titanium are needed for accurate modeling of the corresponding spectra in late-type stars. In this work excitation and charge transfer in low-energy Mn+H and T…
View article: Negative ion relaxation and reactions in a cryogenic storage ring
Negative ion relaxation and reactions in a cryogenic storage ring Open
An overview of recent experimental results of studies of negative atomic and molecular ions in the Double ElectroStatic Ion-Ring ExpEriment, DESIREE is given. Metastable level lifetimes in atomic negative ions have been measured by time-de…
View article: Final state resolved mutual neutralization of Li<sup>+</sup> and D<sup>−</sup>
Final state resolved mutual neutralization of Li<sup>+</sup> and D<sup>−</sup> Open
Synopsis We have performed a merged beam experiment on mutual neutralization of Li + and D − , at center of mass energies close to 0 eV using the DESIREE storage rings. The final state channels Li(3s) and Li(3p+3d) are resolved and the bra…
View article: Theoretical Atomic Spectroscopy of Earthbound and Stellar Plasma
Theoretical Atomic Spectroscopy of Earthbound and Stellar Plasma Open
Motivated by spectroscopic analysis of astrophysical and laboratory plasma, this thesis concerns the fundamental structure and spectral properties of atoms and their ions. The multiconfiguration Dirac-Hartree-Fock (MCDHF) method is used to…
View article: ATOMIC-LEVEL PSEUDO-DEGENERACY OF ATOMIC LEVELS GIVING TRANSITIONS INDUCED BY MAGNETIC FIELDS, OF IMPORTANCE FOR DETERMINING THE FIELD STRENGTHS IN THE SOLAR CORONA
ATOMIC-LEVEL PSEUDO-DEGENERACY OF ATOMIC LEVELS GIVING TRANSITIONS INDUCED BY MAGNETIC FIELDS, OF IMPORTANCE FOR DETERMINING THE FIELD STRENGTHS IN THE SOLAR CORONA Open
We present a measured value for the degree of pseudo-degeneracy between two fine-structure levels in Fe 9+ from line intensity ratios involving a transition induced by an external magnetic field. The extracted fine-structure energy differe…
View article: Energy levels and radiative data for Kr-like W<sup>38+</sup>from MCDHF and RMBPT calculations
Energy levels and radiative data for Kr-like W<sup>38+</sup>from MCDHF and RMBPT calculations Open
Energies, transition rates, line strengths and lifetimes have been computed for all levels of the 4p 6 and 4p 54d configurations of W38+ by using the multi-configuration Dirac-Hartree-Fock (MCDHF) method as well as relativistic many-body p…