Laboratory measurements of the recombination of PAH ions with electrons: implications for the PAH charge state in interstellar clouds.

Ludovic Biennier (1) , Mohamed Alsayed-Ali (1) , Anne Foutel-Richard (1) , Oldrich Novotny (1, 2) , Sophie Carles (3) , Christiane Rebrion-Rowe (1) , Bertrand Rowe (3)

1 PALMS - Physique des atomes, lasers, molécules et surfaces
2 MUNI - Masaryk University [Brno]
3 IPR - Institut de Physique de Rennes

Laboratory measurements of the recombination of polycyclic aromatic hydrocarbon (PAH) ions with electrons are presented. Experimental data have been obtained at room temperature for azulene (C10H8) and acenaphthene (C12H10) cations by the Flowing Afterglow with PhotoIons method. The results confirm that the recombination of PAH ions is fast although well below the geometrical limit. The set of our recent and present measurements reveal a definite trend of increasing rate with the number of carbon atoms of the PAH. This behaviour that needs further characterization is potentially of great interest for charge state models as recombination is a dominant mechanism of PAH ion destruction in the interstellar medium. The design of experiments to measure the recombination of larger PAHs and their temperature dependence is discussed.

Mots clés: Molecular physics; CRESU

Domaines: Biochimie, Biologie Moléculaire; Physique [physics]

Ludovic Biennier, Mohamed Alsayed-Ali, Anne Foutel-Richard, Oldrich Novotny, Sophie Carles, et al.. Laboratory measurements of the recombination of PAH ions with electrons: implications for the PAH charge state in interstellar clouds.. Faraday Discussions, 2006, 133, pp.289-301; discussion 347-74, 449-52. ⟨10.1039/B516858A⟩. ⟨hal-00653379⟩