Few-femtosecond time-resolved study of the UV-induced dissociative dynamics of iodomethane.

Autor: Colaizzi L; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany. lorenzo.colaizzi@polimi.it.; Physics Department, Universität Hamburg, Hamburg, Germany. lorenzo.colaizzi@polimi.it., Ryabchuk S; Physics Department, Universität Hamburg, Hamburg, Germany.; The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Hamburg, Germany., Månsson EP; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany., Saraswathula K; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany., Wanie V; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany., Trabattoni A; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.; Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany., González-Vázquez J; Departamento de Química, Universidad Autonoma de Madrid, Madrid, Spain. jesus.gonzalezv@uam.es.; IADCHEM, Universidad Autónoma de Madrid, Madrid, Spain. jesus.gonzalezv@uam.es., Martín F; Departamento de Química, Universidad Autonoma de Madrid, Madrid, Spain.; Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Madrid, Spain., Calegari F; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany. francesca.calegari@desy.de.; Physics Department, Universität Hamburg, Hamburg, Germany. francesca.calegari@desy.de.; The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Hamburg, Germany. francesca.calegari@desy.de.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2024 Oct 25; Vol. 15 (1), pp. 9196. Date of Electronic Publication: 2024 Oct 25.
DOI: 10.1038/s41467-024-53183-8
Abstrakt: Ultraviolet (UV) light that penetrates our atmosphere initiates various photochemical and photobiological processes. However, the absence of extremely short UV pulses has so far hindered our ability to fully capture the mechanisms at the very early stages of such processes. This is important because the concerted motion of electrons and nuclei in the first few femtoseconds often determines molecular reactivity. Here we investigate the dissociative dynamics of iodomethane following UV photoexcitation, utilizing mass spectrometry with a 5 fs time resolution. The short duration of the UV pump pulse (4.2 fs) allows the ultrafast dynamics to be investigated in the absence of any external field, from well before any significant vibrational displacement occurs until dissociation has taken place. The experimental results combined with semi-classical trajectory calculations provide the identification of the main dissociation channels and indirectly reveal the signature of a conical intersection in the time-dependent yield of the iodine ion. Furthermore, we demonstrate that the UV-induced breakage of the C-I bond can be prevented when the molecule is ionized by the probe pulse within 5 fs after the UV excitation, showcasing an ultrafast stabilization scheme against dissociation.
(© 2024. The Author(s).)
Databáze: MEDLINE
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