Computational Atomic Structures Toward Heavy Element Research
(2021)- Abstract
- We are interested in complex electronic structures of various atomic and ionics systems. We use an ab initio
approach, the multiconfigurational Dirac-Hartree-Fock (MCDHF), to compute atomic structures and properties.
We contribute in three main ways to the already existent literature: by developing and implementing original
computer programs, by investigating possibilities of alternative computational methodologies and strategies, and
finally by performing accurate atomic structure calculations to support other research fields, i.e., nuclear physics,
astrophysics or experimental physics, through the theoretical estimation of relevant atomic data.
We raise questions about the choice of the optimal orbital basis by... (More) - We are interested in complex electronic structures of various atomic and ionics systems. We use an ab initio
approach, the multiconfigurational Dirac-Hartree-Fock (MCDHF), to compute atomic structures and properties.
We contribute in three main ways to the already existent literature: by developing and implementing original
computer programs, by investigating possibilities of alternative computational methodologies and strategies, and
finally by performing accurate atomic structure calculations to support other research fields, i.e., nuclear physics,
astrophysics or experimental physics, through the theoretical estimation of relevant atomic data.
We raise questions about the choice of the optimal orbital basis by considering finite basis sets, MCDHF orbital
bases and natural-orbital bases. We demonstrate the promising potential of the latter in the context of hyperfine
structures and hope that others will find interest in pursuing our analysis. Ultimately, our work put forward some
weaknesses of the traditional optimization strategy based on the layer-by-layer optimization strategy.
We also perform large-scale calculations to determine accurate atomic properties such as energy levels, hyperfine
structures, isotope shifts, transition parameters, radiative lifetimes and Landé g factors. We show through the
variety of atomic properties and atomic systems studied, the difficulty of describing, in the relativistic framework,
the correlation between the spatial position of electrons due to their Coulomb repulsion.
This thesis is organized in two main parts. The first one is dedicated to the theoretical and computational
backgrounds that are needed to understand the theoretical models and the interpretation of our results. The
second part presents and summarizes our articles and manuscripts. They are separated in four groups, A, B, C,
and D, around the themes of the atomic orbital bases, the applications to nuclear physics, the applications to
astrophysics, and investigations of negative ions. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/6c46b233-21d7-4aa6-848d-bbe0a8af6446
- author
- Schiffmann, Sacha LU
- supervisor
- opponent
-
- Professor Santos, José Paulo, New University, Lisboa, Portugal
- organization
- publishing date
- 2021
- type
- Thesis
- publication status
- published
- subject
- keywords
- Atoms, electron correlation, relativity, Quantum mechanics, calculations, natural orbitals, isotope shifts, hyperfine structures, transition parameters, Landé g factor, Fysicumarkivet A:2021:Schiffmann
- pages
- 410 pages
- publisher
- Lund
- defense location
- Rydberg Hall Join via zoom: https://lu-se.zoom.us/j/61578287150?pwd=aloxcHFUZGdLZ1ZEQWt3bHFWTElVUT09, passcode 2020
- defense date
- 2021-05-12 13:00:00
- ISBN
- 978-91-7895-777-4
- 978-91-7895-778-1
- language
- English
- LU publication?
- yes
- id
- 6c46b233-21d7-4aa6-848d-bbe0a8af6446
- date added to LUP
- 2021-04-01 11:38:24
- date last changed
- 2021-07-08 15:11:18
@phdthesis{6c46b233-21d7-4aa6-848d-bbe0a8af6446,
abstract = {{We are interested in complex electronic structures of various atomic and ionics systems. We use an ab initio<br/>approach, the multiconfigurational Dirac-Hartree-Fock (MCDHF), to compute atomic structures and properties.<br/>We contribute in three main ways to the already existent literature: by developing and implementing original<br/>computer programs, by investigating possibilities of alternative computational methodologies and strategies, and<br/>finally by performing accurate atomic structure calculations to support other research fields, i.e., nuclear physics,<br/>astrophysics or experimental physics, through the theoretical estimation of relevant atomic data.<br/>We raise questions about the choice of the optimal orbital basis by considering finite basis sets, MCDHF orbital<br/>bases and natural-orbital bases. We demonstrate the promising potential of the latter in the context of hyperfine<br/>structures and hope that others will find interest in pursuing our analysis. Ultimately, our work put forward some<br/>weaknesses of the traditional optimization strategy based on the layer-by-layer optimization strategy.<br/>We also perform large-scale calculations to determine accurate atomic properties such as energy levels, hyperfine<br/>structures, isotope shifts, transition parameters, radiative lifetimes and Landé g factors. We show through the<br/>variety of atomic properties and atomic systems studied, the difficulty of describing, in the relativistic framework,<br/>the correlation between the spatial position of electrons due to their Coulomb repulsion.<br/>This thesis is organized in two main parts. The first one is dedicated to the theoretical and computational<br/>backgrounds that are needed to understand the theoretical models and the interpretation of our results. The<br/>second part presents and summarizes our articles and manuscripts. They are separated in four groups, A, B, C,<br/>and D, around the themes of the atomic orbital bases, the applications to nuclear physics, the applications to<br/>astrophysics, and investigations of negative ions.}},
author = {{Schiffmann, Sacha}},
isbn = {{978-91-7895-777-4}},
keywords = {{Atoms; electron correlation; relativity; Quantum mechanics; calculations; natural orbitals; isotope shifts; hyperfine structures; transition parameters; Landé g factor; Fysicumarkivet A:2021:Schiffmann}},
language = {{eng}},
publisher = {{Lund}},
school = {{Lund University}},
title = {{Computational Atomic Structures Toward Heavy Element Research}},
year = {{2021}},
}