McGhee, Henry George;
(2025)
Molecular Spectroscopy from a Core
and Valence Perspective.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The work presented in this thesis investigates the electronic structure and dynamics of gas-phase molecular systems using advanced valence and core-level spectroscopic techniques. The research comprises three distinct studies conducted at leading international facilities. In Chapter 3, valence and core photoelectron spectroscopy is applied to a series of substituted disulfide molecules. The findings demonstrate that the splitting between the D₀ and D₁ ionisation bands is a reliable marker for the geometry around the S-S bond. Additionally, X-ray photoelectron spectroscopy (XPS) is shown to be an effective site-selective probe for intramolecular S⋅⋅⋅H bonding sites. This work provides a thorough characterisation of disulfide systems across multiple absorption edges using both XPS and X-ray absorption spectroscopy (XAS). Chapter 4 details a time-resolved X-ray absorption study of ortho- and para-nitroaniline, using a 266 nm pump and probing at the nitrogen K-edge. This study investigates the excited-state dynamics leading to NO elimination, which is found to occur on different timescales for the two isomers. Chapter 5 employs time-resolved photoelectron spectroscopy (TRPES) on cis- and trans-1,2-dichloroethene. Following excitation at 200 nm, the photodissociative pathways are mapped using an extreme ultraviolet (XUV) probe, facilitating the detection of short-lived excited states as well as high binding energy photofragments. Collectively, these studies advance the understanding of the electronic structure and dynamics of molecular systems while also refining methodologies for novel X-ray and XUV based ultrafast spectroscopic techniques.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Molecular Spectroscopy from a Core and Valence Perspective |
| Language: | English |
| Additional information: | Copyright © The Author 2025. 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 Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10209968 |
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