Density functional theory studies of solid density plasmas
<p>In warm dense matter (WDM) and dense plasma physics, Density Functional Theory (DFT) has become a standard approach over the past many years for simulating transport properties, equations of state, interpreting experimental measurements and many other applications. The main chapters, two to...
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| Format: | Thesis |
| Language: | English |
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2019
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| _version_ | 1826315786580393984 |
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| author | Hollebon, P |
| author2 | Vinko, S |
| author_facet | Vinko, S Hollebon, P |
| author_sort | Hollebon, P |
| collection | OXFORD |
| description | <p>In warm dense matter (WDM) and dense plasma physics, Density Functional Theory (DFT) has become a standard approach over the past many years for simulating transport properties, equations of state, interpreting experimental measurements and many other applications. The main chapters, two to four, of this thesis cover original work by the author on three topics: excited state pseudopotentials, time-dependent DFT (TDDFT) and many-body theory.</p>
<p>For an excited state pseudopotential, a specific excited ion core configuration is generated by externally imposing a set of occupation numbers in the same way as can be rigorously done for a non-interacting electron system. In chapter 2 results and a physical argument are presented seeking to justify this process when generating excited configurations of bound electron systems.</p>
<p>Those electrons that might be considered as `free' within a plasma exhibit not only single-particle excitations, as one might label with a set of single-particle occupation numbers, but also significant collective behaviour i.e. plasmons. TDDFT linear-response theory is applied in chapter 3 as a rigorous means of modelling the general dynamic and wavelength-dependent response properties, and fluctuations, for quantum plasma systems. With help from the Langreth rules a fluctuation-dissipation relation for the electron dynamic structure factor is derived. Finally, the dynamic structure factor is computed for compressed Beryllium and CH plasma, with favourable comparison to experimental data and simulations by previous authors.</p>
<p>In chapter four the free-free opacity of solid density Al plasma is considered. Both the tensor nature of the dielectric function, in the form of local field corrections, and an accurate description of bound-state properties, in the form of correct binding energies, are required to reproduce experimental room temperature measurements. Commonly used exchange-correlation functionals are insufficient for predicting the energy gap between bound states and the continuum in a linear response theory context. To this end, the author has implemented and demonstrated finite-temperature many-body quasi-particle calculations in the Abinit code. These many-body calculations are expensive however they are a potential future source of accurate theoretical predictions, covering a wide range of plasma conditions to which other, perhaps simpler models might be benchmarked.</p> |
| first_indexed | 2024-03-07T07:02:43Z |
| format | Thesis |
| id | oxford-uuid:19c9b2f7-1d82-466f-889f-ed9d51ba4479 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-12-09T03:32:31Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | oxford-uuid:19c9b2f7-1d82-466f-889f-ed9d51ba44792024-12-01T15:43:25ZDensity functional theory studies of solid density plasmasThesishttp://purl.org/coar/resource_type/c_db06uuid:19c9b2f7-1d82-466f-889f-ed9d51ba4479Density functionalsTime-dependent density functional theoryHigh-density plasmasPhysicsEnglishHyrax Deposit2019Hollebon, PVinko, SWark, K<p>In warm dense matter (WDM) and dense plasma physics, Density Functional Theory (DFT) has become a standard approach over the past many years for simulating transport properties, equations of state, interpreting experimental measurements and many other applications. The main chapters, two to four, of this thesis cover original work by the author on three topics: excited state pseudopotentials, time-dependent DFT (TDDFT) and many-body theory.</p> <p>For an excited state pseudopotential, a specific excited ion core configuration is generated by externally imposing a set of occupation numbers in the same way as can be rigorously done for a non-interacting electron system. In chapter 2 results and a physical argument are presented seeking to justify this process when generating excited configurations of bound electron systems.</p> <p>Those electrons that might be considered as `free' within a plasma exhibit not only single-particle excitations, as one might label with a set of single-particle occupation numbers, but also significant collective behaviour i.e. plasmons. TDDFT linear-response theory is applied in chapter 3 as a rigorous means of modelling the general dynamic and wavelength-dependent response properties, and fluctuations, for quantum plasma systems. With help from the Langreth rules a fluctuation-dissipation relation for the electron dynamic structure factor is derived. Finally, the dynamic structure factor is computed for compressed Beryllium and CH plasma, with favourable comparison to experimental data and simulations by previous authors.</p> <p>In chapter four the free-free opacity of solid density Al plasma is considered. Both the tensor nature of the dielectric function, in the form of local field corrections, and an accurate description of bound-state properties, in the form of correct binding energies, are required to reproduce experimental room temperature measurements. Commonly used exchange-correlation functionals are insufficient for predicting the energy gap between bound states and the continuum in a linear response theory context. To this end, the author has implemented and demonstrated finite-temperature many-body quasi-particle calculations in the Abinit code. These many-body calculations are expensive however they are a potential future source of accurate theoretical predictions, covering a wide range of plasma conditions to which other, perhaps simpler models might be benchmarked.</p> |
| spellingShingle | Density functionals Time-dependent density functional theory High-density plasmas Physics Hollebon, P Density functional theory studies of solid density plasmas |
| title | Density functional theory studies of solid density plasmas |
| title_full | Density functional theory studies of solid density plasmas |
| title_fullStr | Density functional theory studies of solid density plasmas |
| title_full_unstemmed | Density functional theory studies of solid density plasmas |
| title_short | Density functional theory studies of solid density plasmas |
| title_sort | density functional theory studies of solid density plasmas |
| topic | Density functionals Time-dependent density functional theory High-density plasmas Physics |
| work_keys_str_mv | AT hollebonp densityfunctionaltheorystudiesofsoliddensityplasmas |