Photodissociation dynamics of halogenated aromatic molecules : The case of core-ionized tetrabromothiophene
(2021) In Physical Chemistry Chemical Physics 23(37). p.21249-21261- Abstract
We studied the gas-phase photodissociation of a fully halogenated aromatic molecule, tetrabromothiophene, upon core-shell ionization by using synchrotron radiation and energy-resolved multiparticle coincidence spectroscopy. Photodynamics was initiated by the selective soft X-ray ionization of three elements-C, S, and Br-leading to the formation of dicationic states by Auger decay. From a detailed study of photodissociation upon Br 3d ionization, we formulate a general fragmentation scheme, where dissociation into neutral fragments and a pair of cations prevails, but dicationic species are also produced. We conclude that dicationic tetrabromothiophene typically undergoes deferred charge separation (with one of the ions being often Br+)... (More)
We studied the gas-phase photodissociation of a fully halogenated aromatic molecule, tetrabromothiophene, upon core-shell ionization by using synchrotron radiation and energy-resolved multiparticle coincidence spectroscopy. Photodynamics was initiated by the selective soft X-ray ionization of three elements-C, S, and Br-leading to the formation of dicationic states by Auger decay. From a detailed study of photodissociation upon Br 3d ionization, we formulate a general fragmentation scheme, where dissociation into neutral fragments and a pair of cations prevails, but dicationic species are also produced. We conclude that dicationic tetrabromothiophene typically undergoes deferred charge separation (with one of the ions being often Br+) that may be followed by secondary dissociation steps, depending on the available internal energy of the parent dication. Observations suggest that the ejection of neutral bromine atoms as the first step of deferred charge separation is a prevailing feature in dicationic dissociation, although sometimes in this step the C-Br bonds appear to remain intact and the thiophene ring is broken instead. Ionization-site-specific effects are observed particularly in doubly charged fragments and as large differences in the yields of the intact parent dication. We interpret these effects, using first-principles calculations and molecular dynamics simulations of core-hole states, as likely caused by the geometry changes during the core-hole lifetime.
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- author
- Pihlava, Lassi ; Niskanen, Johannes ; Kooser, Kuno ; Stråhlman, Christian LU ; Maclot, Sylvain LU ; Kivimäki, Antti LU and Kukk, Edwin
- organization
- publishing date
- 2021-10-07
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 23
- issue
- 37
- pages
- 13 pages
- publisher
- Royal Society of Chemistry
- external identifiers
-
- scopus:85116557359
- pmid:34542547
- ISSN
- 1463-9076
- DOI
- 10.1039/d1cp03097c
- language
- English
- LU publication?
- yes
- additional info
- Funding Information: LP acknowledges financial support from The Vilho, Yrjö and Kalle VäisäläFoundation of the Finnish Academy of Science and Letters. JN acknowledges the Academy of Finland for funding via project 331234. SM acknowledges financial support from the Knut and Alice Wallenberg Foundation and the COST Action CA18212 – Molecular Dynamics in the GAS phase (MD-GAS), supported by COST (European Cooperation in Science and Technology). EK acknowledges funding by the Academy of Finland via project 295551. We acknowledge the MAX IV Laboratory for time on Beamline FinEstBeAMS under proposal 20190446. Research conducted at MAX IV, a Swedish national user facility, is supported by the Swedish Research Council under contract 2018-07152, the Swedish Governmental Agency for Innovation Systems under contract 2018-04969, and Formas under contract 2019-02496. Publisher Copyright: © 2021 the Owner Societies.
- id
- adbd40ff-40a3-409e-bfb7-e784e7066fbc
- date added to LUP
- 2021-10-22 10:42:38
- date last changed
- 2024-06-15 18:47:56
@article{adbd40ff-40a3-409e-bfb7-e784e7066fbc,
abstract = {{<p>We studied the gas-phase photodissociation of a fully halogenated aromatic molecule, tetrabromothiophene, upon core-shell ionization by using synchrotron radiation and energy-resolved multiparticle coincidence spectroscopy. Photodynamics was initiated by the selective soft X-ray ionization of three elements-C, S, and Br-leading to the formation of dicationic states by Auger decay. From a detailed study of photodissociation upon Br 3d ionization, we formulate a general fragmentation scheme, where dissociation into neutral fragments and a pair of cations prevails, but dicationic species are also produced. We conclude that dicationic tetrabromothiophene typically undergoes deferred charge separation (with one of the ions being often Br+) that may be followed by secondary dissociation steps, depending on the available internal energy of the parent dication. Observations suggest that the ejection of neutral bromine atoms as the first step of deferred charge separation is a prevailing feature in dicationic dissociation, although sometimes in this step the C-Br bonds appear to remain intact and the thiophene ring is broken instead. Ionization-site-specific effects are observed particularly in doubly charged fragments and as large differences in the yields of the intact parent dication. We interpret these effects, using first-principles calculations and molecular dynamics simulations of core-hole states, as likely caused by the geometry changes during the core-hole lifetime. </p>}},
author = {{Pihlava, Lassi and Niskanen, Johannes and Kooser, Kuno and Stråhlman, Christian and Maclot, Sylvain and Kivimäki, Antti and Kukk, Edwin}},
issn = {{1463-9076}},
language = {{eng}},
month = {{10}},
number = {{37}},
pages = {{21249--21261}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{Photodissociation dynamics of halogenated aromatic molecules : The case of core-ionized tetrabromothiophene}},
url = {{http://dx.doi.org/10.1039/d1cp03097c}},
doi = {{10.1039/d1cp03097c}},
volume = {{23}},
year = {{2021}},
}