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

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

Journal Article (2018)

Author(s)

Nolan Foley (University Medical Center Groningen)

S. Cazaux (Universiteit Leiden, TU Delft - Astrodynamics & Space Missions)

D. Egorov (University Medical Center Groningen)

L. M.P.V. Boschman (Rijksuniversiteit Groningen, University Medical Center Groningen)

R. Hoekstra (University Medical Center Groningen)

T. Schlathölter (University Medical Center Groningen)

Astrochemistry ISM: molecules Molecular processes

DOI related publication

https://doi.org/10.1093/mnras/sty1528 Final published version

To reference this document use

https://resolver.tudelft.nl/uuid:cdb51425-052d-4702-8aaf-93044c3df411

More Info

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Publication Year

2018

Language

English

Journal title

Monthly Notices of the Royal Astronomical Society

Issue number

1

Volume number

479

Pages (from-to)

649-656

Downloads counter

235

Abstract

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.