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

• DOI: 10.1093/mnras/sty1528
• Publication Date: 2018-06-08T11:08:24Z
• Authors: Nolan Foley; S Cazaux; D Egorov; L M P V Boschman; R Hoekstra; T Schlathölter
• Keywords: Coronene; Hydrogen atom abstraction; Polycyclic aromatic hydrocarbon

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