Mapping the complete reaction path of a complex photochemical reaction
Mapping the complete reaction path of a complex photochemical reaction
We probe the dynamics of dissociating CS2 molecules across the entire reaction pathway upon excitation. Photoelectron spectroscopy measurements using laboratory-generated femtosecond extreme ultraviolet pulses monitor the competing dissociation, internal conversion, and intersystem crossing dynamics. Dissociation occurs either in the initially excited singlet manifold or, via intersystem crossing, in the triplet manifold. Both product channels are monitored and show that despite being more rapid, the singlet dissociation is the minor product and that triplet state products dominate the final yield. We explain this by consideration of accurate potential energy curves for both the singlet and triplet states. We propose that rapid internal conversion stabilises the singlet population dynamically, allowing for singlet-triplet relaxation via intersystem crossing and efficient formation of spin-forbidden dissociation products on longer timescales. The study demonstrates the importance of measuring the full reaction pathway for defining accurate reaction mechanisms.
Smith, Adam D.
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Warne, Emily M.
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Bellshaw, Darren
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Horke, Daniel
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Tudorovskya, Maria
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Springate, Emma
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Jones, Alfred
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Cacho, Cephise
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Chapman, Richard T.
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Kirrander, Adam
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Minns, Russell S.
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4 May 2018
Smith, Adam D.
af4cf6b6-1d87-47e7-a6f6-c8cc0ea20af8
Warne, Emily M.
63799bdf-67fa-4dd8-adac-b963a9587a28
Bellshaw, Darren
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Horke, Daniel
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Tudorovskya, Maria
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Springate, Emma
f3004731-cf69-48bc-9816-1300a2276191
Jones, Alfred
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Cacho, Cephise
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Chapman, Richard T.
e74a000f-babe-4fd8-ad9e-64f2ec405724
Kirrander, Adam
acf8c1fa-3f09-4b55-ae96-34a40856b7df
Minns, Russell S.
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Smith, Adam D., Warne, Emily M., Bellshaw, Darren, Horke, Daniel, Tudorovskya, Maria, Springate, Emma, Jones, Alfred, Cacho, Cephise, Chapman, Richard T., Kirrander, Adam and Minns, Russell S.
(2018)
Mapping the complete reaction path of a complex photochemical reaction.
Physical Review Letters, 120 (18), [183003].
(doi:10.1103/PhysRevLett.120.183003).
Abstract
We probe the dynamics of dissociating CS2 molecules across the entire reaction pathway upon excitation. Photoelectron spectroscopy measurements using laboratory-generated femtosecond extreme ultraviolet pulses monitor the competing dissociation, internal conversion, and intersystem crossing dynamics. Dissociation occurs either in the initially excited singlet manifold or, via intersystem crossing, in the triplet manifold. Both product channels are monitored and show that despite being more rapid, the singlet dissociation is the minor product and that triplet state products dominate the final yield. We explain this by consideration of accurate potential energy curves for both the singlet and triplet states. We propose that rapid internal conversion stabilises the singlet population dynamically, allowing for singlet-triplet relaxation via intersystem crossing and efficient formation of spin-forbidden dissociation products on longer timescales. The study demonstrates the importance of measuring the full reaction pathway for defining accurate reaction mechanisms.
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Accepted/In Press date: 23 March 2018
e-pub ahead of print date: 4 May 2018
Published date: 4 May 2018
Identifiers
Local EPrints ID: 419220
URI: http://eprints.soton.ac.uk/id/eprint/419220
ISSN: 1079-7114
PURE UUID: a3dae671-6137-4060-91b7-318af6e4f915
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Date deposited: 09 Apr 2018 16:30
Last modified: 16 Mar 2024 06:25
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Contributors
Author:
Adam D. Smith
Author:
Emily M. Warne
Author:
Darren Bellshaw
Author:
Daniel Horke
Author:
Maria Tudorovskya
Author:
Emma Springate
Author:
Alfred Jones
Author:
Cephise Cacho
Author:
Richard T. Chapman
Author:
Adam Kirrander
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