Ultrafast dynamics in polycyclic aromatic hydrocarbons: the key case of conical intersections at higher excited states and their role in the photophysics of phenanthrene monomer

Nazari, M.; Bösch, C. D.; Rondi, A.; Francés-Monerris, A.; Marazzi, M.; Lognon, E.; Gazzetto, M.; Langenegger, S.M.; Häner, R.; Feurer, T.; Monari, A.; Cannizzo, A. (2019). Ultrafast dynamics in polycyclic aromatic hydrocarbons: the key case of conical intersections at higher excited states and their role in the photophysics of phenanthrene monomer. Physical Chemistry Chemical Physics, 21(31), pp. 16981-16988. Royal Society of Chemistry 10.1039/C9CP03147B

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In this study we reveal the detailed photocycle of a phenanthrene monomer. Phenanthrene serves as a popular building block for supramolecular systems and as an archetypal molecule to study the photochemistry of polycyclic aromatic hydrocarbons. By means of femtosecond time-resolved UV-vis transient absorption spectroscopy and molecular modeling, we found that the first bright transition involves the second excited singlet state, which relaxes toward the lowest excited singlet state with a biphasic internal conversion through a conical intersection region: a fast coherent branching followed by an exceptionally slow (∼ps) incoherent internal conversion. We succeeded to pinpoint the complete relaxation pathways and to extract the relevant parameters, e.g., the branching ratio at the conical intersection and internal conversion rates.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Applied Physics
08 Faculty of Science > Departement of Chemistry and Biochemistry
08 Faculty of Science > Institute of Applied Physics > NCCR MUST

UniBE Contributor:

Nazari Haghighi Pashaki, Maryam; Langenegger, Simon Matthias; Häner, Robert; Feurer, Thomas and Cannizzo, Andrea

Subjects:

600 Technology > 620 Engineering
500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
500 Science > 530 Physics

ISSN:

1463-9076

Publisher:

Royal Society of Chemistry

Funders:

[4] Swiss National Science Foundation
[UNSPECIFIED] NCCR MUST
[UNSPECIFIED] ERC Starting Grant 279599
[UNSPECIFIED] French ANR
[UNSPECIFIED] Spanish Government (CTQ2017-87054-C2-2-P)

Language:

English

Submitter:

Robert Häner

Date Deposited:

02 Mar 2020 15:14

Last Modified:

02 Mar 2020 15:14

Publisher DOI:

10.1039/C9CP03147B

BORIS DOI:

10.7892/boris.141004

URI:

https://boris.unibe.ch/id/eprint/141004

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