Molecular hydrogen formation on interstellar PAHs through Eley-Rideal abstraction reactions

Nolan Foley, S. Cazaux, D. Egorov, L. M.P.V. Boschman, R. Hoekstra, T. Schlathölter*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

10 Citations (Scopus)


We present experimental data on H2 formation processes on gas-phase polycyclic aromatic hydrocarbon (PAH) cations. This process was studied by exposing coronene radical cations, confined in a radio-frequency ion trap, to gas-phase H atoms. Sequential attachment of up to 23 hydrogen atoms has been observed. Exposure to atomic D instead of H allows one to distinguish attachment from competing abstraction reactions, as the latter now leave a unique fingerprint in the measured mass spectra. Modelling of the experimental results using realistic cross-sections and barriers for attachment and abstraction yield a 1:2 ratio of abstraction to attachment cross-sections. The strong contribution of abstraction indicates that H2 formation on interstellar PAH cations is an order of magnitude more relevant than previously thought.

Original languageEnglish
Pages (from-to)649-656
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 1 Sep 2018


  • Astrochemistry
  • ISM: molecules
  • Molecular processes


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