4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
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Contribution Contributed Talk

Hans Harnack Haus -
FROM DENSE CORES TO PROTOSTARS 2

The hydrogenation of PAH cations: A journey guided by stability and magic numbers.

Speakers

  • Ms. stephanie CAZAUX

Primary authors

Co-authors

Content

The understanding of hydrogen attachment to carbonaceous surfaces is essential to a wide variety of research fields and technologies such as hydrogen storage for transportation but also for the formation of cosmic H2 and the identification of stable PAHs in space. For coronene cations as prototypical Polycyclic Aromatic Hydrocarbon (PAH), the existence of magic numbers upon hydrogenation was uncovered experimentally. Quantum chemistry calculations show that hydrogenation follows a site-specific sequence leading to the appearance of stable cations having 5, 11, or 17 hydrogen atoms attached, exactly the magic numbers found in the experiments. For these stable closed-shell cations, further hydrogenation requires appreciable structural changes associated with a high transition barrier. The occurrence of stable superhydrogenated PAHs is fundamental to identify PAHs in space and assess their contribution to the formation of H2.