Atomic hydrogen interactions with small polycyclic aromatic hydrocarbons cations

The European Physical Journal D, vol. 74

Abstract

Abstract When exposed to a thermal beam of hydrogen atoms, gas-phase coronene cations C24H12+ can be sequentially hydrogenated. This process is accompanied by a gradual transition of the electronic structure from aromatic to aliphatic. The planar very stable coronene structure transforms into the significantly weaker corrugated structure, typical for aliphatic molecules. In this study, we have investigated the hydrogenation of 5 smaller polycyclic aromatic hydrocarbon cations using a combination of radiofrequency ion trapping with time-of-flight mass spectrometry. Anthracene (C14H10+), pyrene (C16H10+), triphenylene (C18H12+), tetracene (C18H12+) and 8-9-benzofluoranthene (C20H12+) only cover a small mass range, but differ in carbon/hydrogen ratio, number of outer-edge sites and overall structure. We have observed qualitatively similar initial hydrogenation patterns for all 5 molecular ions, with odd hydrogenation states being dominant. Strong quantitative differences in hydrogenation and in attachment-induced fragmentation were found. For the case of pyrene cations, we have also investigated exposure to atomic D. Clear lines of evidence for HD/D2 abstraction reactions of Eley–Rideal type were found, as previously observed for coronene cations. Graphical abstract

Authors 7

1. Thomas Schlathölter corresponding

   University of Groningen · Zernike Institute for Advanced Materials

   Affiliation as printed

   Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands

2. Yahia Y. Mostafa

   University of Groningen · Zernike Institute for Advanced Materials

   Affiliation as printed

   Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands

3. Amber Kamman

   University of Groningen · Zernike Institute for Advanced Materials

   Affiliation as printed

   Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands

4. Arnold Dongelmans

   University of Groningen · Zernike Institute for Advanced Materials

   Affiliation as printed

   Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands

5. Yann Arribard

   University of Groningen · Zernike Institute for Advanced Materials

   Affiliation as printed

   Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands

6. Stéphanie M. Cazaux Aachen

   Leiden University · Delft University of Technology

   Affiliation as printed

   Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft, The Netherlands

   University of Leiden, P.O. Box 9513, 2300 RA, Leiden, The Netherlands

7. R. Hoekstra

   University of Groningen · Zernike Institute for Advanced Materials

   Affiliation as printed

   Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands