Time-resolved studies of photoinduced dynamics using fast imaging sensors
<p>In this thesis, the three-dimensional, multi-mass, and covariance imaging capabilities of the Pixel Imaging Mass Spectrometry (PImMS) camera has been demonstrated in a range of velocity-map imaging (VMI) experiments.</p> <p>The development of an experimental configuration for V...
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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2020
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| _version_ | 1797086359231397888 |
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| author | Mason, R |
| author2 | Brouard, M |
| author_facet | Brouard, M Mason, R |
| author_sort | Mason, R |
| collection | OXFORD |
| description | <p>In this thesis, the three-dimensional, multi-mass, and covariance imaging capabilities
of the Pixel Imaging Mass Spectrometry (PImMS) camera has been demonstrated
in a range of velocity-map imaging (VMI) experiments.</p>
<p>The development of an experimental configuration for VMI experiments allows for
three-dimensional imaging with high velocity resolution along the time-of-flight axis.
This was demonstrated by recording the full three-dimensional velocity distributions
of CO and S photofragments, following the photodissociation of OCS, with the
PImMS camera. The resultant velocity distributions are sufficiently well resolved
to express as an expansion of spherical harmonics. This was further emphasised
through the investigation of a system with no axis of cylindrical symmetry and
therefore unsuitable for simple conventional VMI experiments.</p>
<p>The ultraviolet (UV) photoexcitation dynamics (λ = 267 nm) of 2(5H)-thiophenone
were studied by ultrafast time-resolved Coulomb explosion imaging. The Coulomb
explosion of the system was probed separately via strong-field and inner-shell
ionisation. The velocity-dependent ion channels arising from an intense non-resonant
infrared (IR) (λ = 801 nm) probe provide information on the photoexcitation
dynamics of thiophenone. The channels derived from Coulomb explosions are
supported through covariance analysis. The photoexcitation scheme and delaydependent
covariance analysis are tentatively attributed to a prompt ring-opening
of thiophenone, within 300 fs. The UV photoexcitation of thiophenone probed via
XUV ionisation revealed many ion correlations were revealed through time-of-flight
covariance analysis, supported by angular covariance. The velocity-dependent
ion yields are notably different to the UV-IR which is unsurprising given the
nature of ionisation.</p>
<p>Coulomb explosion imaging experiments of OCS were performed induced by an
intense IR pulse at varying laser intensities. The rich and complicated Coulomb
explosion dynamics were determined through various covariance analyses. Through
these analyses, minor channels and branching ratios were identified.</p> |
| first_indexed | 2024-03-07T02:20:53Z |
| format | Thesis |
| id | oxford-uuid:a3de685f-d283-4e83-ae0d-98a2a09b67c2 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:20:53Z |
| publishDate | 2020 |
| record_format | dspace |
| spelling | oxford-uuid:a3de685f-d283-4e83-ae0d-98a2a09b67c22022-03-27T02:30:07ZTime-resolved studies of photoinduced dynamics using fast imaging sensorsThesishttp://purl.org/coar/resource_type/c_db06uuid:a3de685f-d283-4e83-ae0d-98a2a09b67c2Chemistry, Physical and theoreticalEnglishHyrax Deposit2020Mason, RBrouard, MBanares, LHeazlewood, B<p>In this thesis, the three-dimensional, multi-mass, and covariance imaging capabilities of the Pixel Imaging Mass Spectrometry (PImMS) camera has been demonstrated in a range of velocity-map imaging (VMI) experiments.</p> <p>The development of an experimental configuration for VMI experiments allows for three-dimensional imaging with high velocity resolution along the time-of-flight axis. This was demonstrated by recording the full three-dimensional velocity distributions of CO and S photofragments, following the photodissociation of OCS, with the PImMS camera. The resultant velocity distributions are sufficiently well resolved to express as an expansion of spherical harmonics. This was further emphasised through the investigation of a system with no axis of cylindrical symmetry and therefore unsuitable for simple conventional VMI experiments.</p> <p>The ultraviolet (UV) photoexcitation dynamics (λ = 267 nm) of 2(5H)-thiophenone were studied by ultrafast time-resolved Coulomb explosion imaging. The Coulomb explosion of the system was probed separately via strong-field and inner-shell ionisation. The velocity-dependent ion channels arising from an intense non-resonant infrared (IR) (λ = 801 nm) probe provide information on the photoexcitation dynamics of thiophenone. The channels derived from Coulomb explosions are supported through covariance analysis. The photoexcitation scheme and delaydependent covariance analysis are tentatively attributed to a prompt ring-opening of thiophenone, within 300 fs. The UV photoexcitation of thiophenone probed via XUV ionisation revealed many ion correlations were revealed through time-of-flight covariance analysis, supported by angular covariance. The velocity-dependent ion yields are notably different to the UV-IR which is unsurprising given the nature of ionisation.</p> <p>Coulomb explosion imaging experiments of OCS were performed induced by an intense IR pulse at varying laser intensities. The rich and complicated Coulomb explosion dynamics were determined through various covariance analyses. Through these analyses, minor channels and branching ratios were identified.</p> |
| spellingShingle | Chemistry, Physical and theoretical Mason, R Time-resolved studies of photoinduced dynamics using fast imaging sensors |
| title | Time-resolved studies of photoinduced dynamics using fast imaging sensors |
| title_full | Time-resolved studies of photoinduced dynamics using fast imaging sensors |
| title_fullStr | Time-resolved studies of photoinduced dynamics using fast imaging sensors |
| title_full_unstemmed | Time-resolved studies of photoinduced dynamics using fast imaging sensors |
| title_short | Time-resolved studies of photoinduced dynamics using fast imaging sensors |
| title_sort | time resolved studies of photoinduced dynamics using fast imaging sensors |
| topic | Chemistry, Physical and theoretical |
| work_keys_str_mv | AT masonr timeresolvedstudiesofphotoinduceddynamicsusingfastimagingsensors |