eprintid: 10068243 rev_number: 31 eprint_status: archive userid: 608 dir: disk0/10/06/82/43 datestamp: 2019-03-14 11:55:17 lastmod: 2020-06-14 08:09:23 status_changed: 2019-03-14 11:55:17 type: thesis metadata_visibility: show creators_name: Banks, Henry Isaac Bryan title: Exotic forms of matter created by interactions with free-electron lasers ispublished: unpub divisions: UCL divisions: A01 divisions: B04 divisions: C06 keywords: Physics, Atomic, Auger, FEL, Nitrogen, Argon note: Copyright © The Author 2019. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/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. abstract: In this thesis, we investigate the formation of atomic and molecular states with mul- tiple core electrons missing. These multiple-core-hole (MCH) states are of interest due to their sensitivity to their chemical environment. These MCH states are formed by successive single-photon ionisations of core electrons. This can be achieved by x-ray photons and a sufficiently large intensity such that the photo-ionisation rate competes with the Auger decay rate of core-hole states. To understand the pathways that lead to the formation of MCH states, we study the interaction of free-electron laser (FEL) pulses with atoms and molecules. These lasers are capable of producing short, high-intensity pulses with high photon en- ergy, which make them ideal for forming MCH states. In order to understand the interaction of an FEL with an atom or molecule, we model these interactions com- putationally. We construct rate equations and track how the population of an atom or molecule transitions between different states. These rate equations involve single- photon ionization processes and Auger transitions. To account for these processes, we compute photo-ionisation cross-sections and Auger decay rates. We develop a computational model that allows us to calculate the ion yields produced when an atom or molecule interacts with an FEL pulse. Further, by calcu- lating how the population transitions via different pathways of intermediate atomic and molecular states, we determine the proportion of the population which accesses MCH states. We also compute electron spectra, which provide measurable observ- ables indicating the formation of MCH states. date: 2019-02-28 date_type: published oa_status: green full_text_type: other thesis_class: doctoral_open thesis_award: Ph.D language: eng thesis_view: UCL_Thesis primo: open primo_central: open_green verified: verified_manual elements_id: 1630334 lyricists_name: Banks, Henry lyricists_id: HBANK64 actors_name: Nonhebel, Lucinda actors_id: LNONH33 actors_role: owner full_text_status: public pagerange: 1-1 pages: 144 event_title: UCL institution: UCL (University College London) department: Physics & Astronomy thesis_type: Doctoral editors_name: Emmanouilidou, A citation: Banks, Henry Isaac Bryan; (2019) Exotic forms of matter created by interactions with free-electron lasers. Doctoral thesis (Ph.D), UCL (University College London). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10068243/1/ThesisHenryBanksCorrections.pdf