Chen, Ahai;
(2017)
Multi-centre molecules driven by intense laser fields.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
In this dissertation we investigate the underlying mechanisms for double ionisation in atoms and frustrated double ionisation in multi-centre molecules. We first study the main mechanisms that underlie non-sequential double ionisation in atoms that are driven by near-single-cycle intense laser fields. Unlike long laser pulses, short ones allow for an easier comparison between theory and experiment. We compare several very recently measured experimental quantities for strongly-driven $Ar$ with our computational results and find good agreement. Next, we investigate double ionisation, frustrated double ionisation, frustrated single ionisation in two-electron triatomic molecules. We compare our computational results for the sum of the kinetic energies of the final ion fragments for double ionisation and for frustrated double ionisation with experimental results. We find very good agreement, particularly for frustrated double ionisation. Moreover, we find that, as for diatomic molecules, two pathways prevail in frustrated ionisation of two-electron triatomic molecules. Only in one of these pathways electron-electron correlation plays an important role. For non-sequential double ionisation, it is well established both theoretically and experimentally that electron-electron correlation plays an important role. However, this is not the case for frustrated double ionisation. We identify a scheme of two colour, orthogonally polarised laser fields that can control the strength of the electron-electron correlation in frustrated double ionisation as a function of the time delay between the two laser pulses. Therefore, based on our proposed combination of laser pulses future experiments can demonstrate the role of electron-electron correlation in frustrated double ionisation.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Multi-centre molecules driven by intense laser fields |
| Event: | University College London |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| UCL classification: | UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10025258 |
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