Soft-x-ray spectroscopy of 
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 and 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mo>(</mml:mo><mml:mtext>coronene</mml:mtext><mml:mo>+</mml:mo><mml:mi mathvariant="normal">H</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mo>+</mml:mo></mml:msup></mml:math>
 cations: The influence of hydrogenation on electronic structure and p

Huo, Yining; Cangahuala, Mónica K. Espinoza; Goulart, Marcelo; Zamudio-Bayer, Vicente; Kubin, Markus; Timm, Martin; Lau, J. Tobias; Issendorff, Bernd von; Hoekstra, Ronnie; Faraji, Shirin; Schlathölter, Thomas

doi:10.1103/physreva.106.063104

Cited by 3 publications

(1 citation statement)

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“…We show that there are pathways to form carbon chains, clusters, and other relevant molecular fragments by irradiating PAHs, which have been already been observed in X-ray induced photodissociation. 39–41 Lastly, we discuss the astrophysical implications of the fragmentation patterns mentioned here – namely that they may provide clues about potential DIB carriers that come from the dissociation of the (partially) dehydrogenated parent.…”

Section: Introductionmentioning

confidence: 95%

Laser-induced fragmentation of coronene cations

Panchagnula,

Kamer,

Candian

et al. 2024

Phys. Chem. Chem. Phys.

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Section: Introductionmentioning

confidence: 95%

Laser-induced fragmentation of coronene cations

Panchagnula,

Kamer,

Candian

et al. 2024

Phys. Chem. Chem. Phys.

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An X-ray spectroscopy study of structural stability of superhydrogenated pyrene derivatives

Huo

Cangahuala

Zamudio-Bayer

et al. 2023

Monthly Notices of the Royal Astronomical Society

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The stability of polycyclic aromatic hydrocarbons (PAHs) upon soft X-ray absorption is of crucial relevance for PAH survival in X-ray dominated regions (XDRs). PAH stability depends on molecular size but also on the degree of hydrogenation that is related to H2 formation in the interstellar medium (ISM). In this project, we intend to reveal the changes of electronic structure caused by hydrogenation and the impact of hydrogenation on the stability of the carbon backbone for cationic pyrene and its hydrogenated derivatives by analysis of near C K-edge soft X-ray photoions. In our experiments, the PAH cations were trapped in a cryogenic radiofrequency (RF) linear ion trap and exposed to monochromatic X-rays with energies from 279 eV to 300 eV. The photo-products were mass-analyzed by means of time-of-flight (TOF) spectroscopy. Partial ion yields (PIYs) were then studied as a function of photon energy. X-ray absorption spectra computed by time-dependent density functional theory (TD-DFT) aided the interpretation of the experimental results. A very good agreement between experimental data and TDDFT with short-range corrected (SRC) functionals for all PAH ions was reached. The near-edge X-ray absorption mass spectra (NEXAMS) exhibit clear peaks due to C 1s transitions to singly occupied molecular orbitals SOMO and to low-lying unoccupied molecular orbitals. In contrast to coronene cations, where hydrogen attachment drastically increases photostability of coronene, the influence of hydrogenation on photostability is substantially weaker for pyrene cations. Here, hydrogen attachment even destabilizes the molecular structure. An astrophysical model describes the half-life of PAH ions in interstellar environments.

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A comparative laboratory study of soft X-ray-induced ionization and fragmentation of five small PAH cations

Huo,

Cangahuala,

Zamudio-Bayer

et al. 2023

Eur. Phys. J. D

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The interaction between polycyclic aromatic hydrocarbon (PAH) radical cations and X-rays predominantly leads to photofragmentation, a process that strongly depends on PAH size and geometry. In our experiments, five prototypical PAHs were exposed to monochromatic soft X-ray photons with energies in the C K-edge regime. As a function of soft X-ray photon energy, photoion yields were obtained by means of time-of-flight mass spectrometry. The resulting near-edge X-ray absorption mass spectra were interpreted using time-dependent density functional theory (TD-DFT) with a short-range corrected functional. We found that the carbon backbone of anthracene$$^+$$ + (C$$_{14}$$ 14 H$$_{10}^+$$ 10 + ), pyrene$$^+$$ + (C$$_{16}$$ 16 H$$_{10}^+$$ 10 + ) and coronene$$^+$$ + (C$$_{24}$$ 24 H$$_{12}^+$$ 12 + ) can survive soft X-ray absorption, even though mostly intermediate size fragments are formed. In contrast, for hexahydropyrene$$^+$$ + (C$$_{16}$$ 16 H$$_{16}^+$$ 16 + ) and triphenylene$$^+$$ + (C$$_{18}$$ 18 H$$_{12}^+$$ 12 + ) molecular survival is not observed and the fragmentation pattern is dominated by small fragments. For a given excitation energy, molecular survival evidently does not simply correlate with PAH size but strongly depends on other PAH properties. Graphic abstract

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Soft-x-ray spectroscopy of coronene+ and (coronene+H)+ cations: The influence of hydrogenation on electronic structure and p

Cited by 3 publications

References 56 publications

Laser-induced fragmentation of coronene cations

Laser-induced fragmentation of coronene cations

An X-ray spectroscopy study of structural stability of superhydrogenated pyrene derivatives

A comparative laboratory study of soft X-ray-induced ionization and fragmentation of five small PAH cations

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