H2 catalysis through superhydrogenation of interstellar polycyclic aromatic hydrocarbons
Frederik Doktor S Simonsen1, Pernille A Jensen1, Anders W Skov1
1Department of Physics & Astronomy, Aarhus University, 8000 Aarhus C, Denmark.
Proceedings of the International Astronomical Union. International Astronomical Union
|October 19, 2020
Summary
This study shows how neutral polycyclic aromatic hydrocarbons (PAHs) like coronene react with atomic hydrogen. Researchers observed stable superhydrogenated PAHs, revealing insights into their chemical behavior.
Area of Science:
- Surface science
- Physical chemistry
- Materials science
Background:
- Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous in various environments.
- Understanding PAH reactivity is crucial for fields ranging from astrochemistry to materials science.
- Superhydrogenation, the addition of multiple hydrogen atoms, significantly alters PAH properties.
Purpose of the Study:
- To investigate the superhydrogenation of neutral PAHs using atomic hydrogen.
- To characterize the resulting superhydrogenated species and their stability.
- To determine the initial reaction cross-section for the superhydrogenation of coronene.
Main Methods:
- Preparation of neutral PAH (coronene, pentacene, pentacenequinone) monolayers on highly oriented pyrolytic graphite (HOPG).
- Exposure of PAH monolayers to a beam of atomic hydrogen.
- Analysis of superhydrogenated PAH species using temperature-programmed desorption (TPD) measurements.
Main Results:
- Observation of stable intermediate and fully superhydrogenated PAH species.
- Evidence of controlled superhydrogenation degrees on the graphite surface.
- Determination of the initial reaction cross-section for coronene superhydrogenation.
Conclusions:
- Atomic hydrogen readily induces superhydrogenation in neutral PAHs like coronene.
- Superhydrogenated PAHs exhibit distinct stable states under experimental conditions.
- The determined reaction cross-section provides quantitative data for PAH-hydrogen interactions.
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