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

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

doi:10.1140/epjd/s10053-023-00763-w

2024 Impact factor 1.5

Atomic, Molecular, Optical and Plasma Physics

Open Access

Eur. Phys. J. D (2023) 77: 181
https://doi.org/10.1140/epjd/s10053-023-00763-w

Regular Article - Atomic and Molecular Collisions

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

Yining Huo¹, Mónica K. Espinoza Cangahuala¹, Vicente Zamudio-Bayer², Marcelo Goulart¹, Markus Kubin², Martin Timm², J. Tobias Lau²^,3, Bernd von Issendorff³, Ronnie Hoekstra¹^,4, Shirin Faraji¹ and Thomas Schlathölter¹^,5^m

¹ Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
² Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489, Berlin, Germany
³ Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, 79104, Freiburg, Germany
⁴ Advanced Research Center for Nanolithography (ARCNL), Science Park 106, 1098 XG, Amsterdam, The Netherlands
⁵ University College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG, Groningen, The Netherlands

^m t.a.schlatholter@rug.nl

Received: 14 July 2023
Accepted: 25 September 2023
Published online: 16 October 2023

Abstract

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.

Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjd/s10053-023-00763-w.

© The Author(s) 2023

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