Peters, Matthew;
(2023)
Correlated three-electron ionization in strongly-driven atoms and molecules.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
We develop a theoretical model to study correlated three-electron ionization. We examine the strongly-driven linear triatomic molecule HeH2+. To account for unphysical autoionization where one bound electron collapses into the nucleus exchanging infinite energy with another bound electron, we turn off the Coulomb force between any pair of bound electrons. Also, we construct an algorithm to determine on the fly during time propagation when an electron is bound or quasifree. This model can address double and triple ionization but cannot describe processes involving two bound electrons. Hence, we cannot address frustrated double ionization with one ionizing electron, one deeply bound electron and another electron in a Rydberg state. These limitations led us to develop a sophisticated model that accounts for the interaction of any pair of bound electrons via effective potentials. The interaction between any pair of quasifree and bound electrons as well as between quasifree electrons is described by the full Coulomb forces. We do so by introducing a set of criteria that identifies on the fly during time propagation when an electron is bound or quasifree. The results provided by our model for the momenta distributions for triple and double ionization of strongly driven Ar and Ne have very good to excellent agreement with experimental results, unlike previous models. Currently our model is the most accurate one for describing multi-electron ionization in strongly driven atoms. Finally, we investigate non-dipole effects in the correlated multielectron ionization of Ar and Ne. We identify a positive momentum offset in the average sum of the final electron momenta along the direction of light propagation. We find that the magnitude of this momentum offset probes the strength of a recollision, i.e. the strength of electron-electron correlation, during multi-electron ionization.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Correlated three-electron ionization in strongly-driven atoms and molecules |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10181090 |
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