Formation of H{sub 2} from internally heated polycyclic aromatic hydrocarbons: Excitation energy dependence

Journal Article · Tue Apr 14 00:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4917021· OSTI ID:22415637

Gatchell, M.; Stockett, M. H.; Schmidt, H. T.; Cederquist, H.; Delaunay, R.; Rousseau, P.; Adoui, L. ^[1]; Domaracka, A.; Huber, B. A. ^[1]; Micelotta, E. R. ^[2]

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1. CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France)
2. Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France)

We have investigated the effectiveness of molecular hydrogen (H{sub 2}) formation from Polycyclic Aromatic Hydrocarbons (PAHs) which are internally heated by collisions with keV ions. The present and earlier experimental results are analyzed in view of molecular structure calculations and a simple collision model. We estimate that H{sub 2} formation becomes important for internal PAH temperatures exceeding about 2200 K, regardless of the PAH size and the excitation agent. This suggests that keV ions may effectively induce such reactions, while they are unlikely due to, e.g., absorption of single photons with energies below the Lyman limit. The present analysis also suggests that H{sub 2} emission is correlated with multi-fragmentation processes, which means that the [PAH-2H]{sup +} peak intensities in the mass spectra may not be used for estimating H{sub 2}-formation rates.

• OSTI ID: 22415637
• Journal Information: Journal of Chemical Physics, Vol. 142, Issue 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
ENERGY DEPENDENCE
EXCITATION
HYDROGEN
ION COLLISIONS
KEV RANGE
MASS SPECTRA
MOLECULAR IONS
MOLECULAR STRUCTURE
PHOTONS
POLYCYCLIC AROMATIC HYDROCARBONS