title: Photoionization of cold gas phase coronene and its clusters: autoionization resonances in monomer, dimer, and trimer and electronic structure of monomer cation.
abstract: Polycyclic aromatic hydrocarbons (PAHs) are key species encountered in a large variety of environments such as the Interstellar Medium (ISM) and in combustion media. Their UV spectroscopy and photodynamics in neutral and cationic forms are important to investigate in order to learn about their structure, formation mechanisms, and reactivity. Here, we report an experimental photoelectron-photoion coincidence study of a prototypical PAH molecule, coronene, and its small clusters, in a molecular beam using the vacuum ultraviolet (VUV) photons provided by the SOLEIL synchrotron facility. Mass-selected high resolution threshold photoelectron (TPES) and total ion yield spectra were obtained and analyzed in detail. Intense series of autoionizing resonances have been characterized as originating from the monomer, dimer, and trimer neutral species, which may be used as spectral fingerprints for their detection in the ISM by VUV absorption spectroscopy. Finally, a full description of the electronic structure of the monomer cation was made and discussed in detail in relation to previous spectroscopic optical absorption data. Tentative vibrational assignments in the near-threshold TPES spectrum of the monomer have been made with the support of a theoretical approach based on density functional theory.
authors.affiliation: Institut des Sciences Moléculaires d'Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bréchignac
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette, France.
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Garcia
authors.affiliation: Institut des Sciences Moléculaires d'Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Falvo
authors.affiliation: IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Joblin
authors.affiliation: IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4, France.
authors.forename: Damian
authors.initials: D
authors.lastname: Kokkin
authors.affiliation: IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Bonnamy
authors.affiliation: Institut des Sciences Moléculaires d'Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Parneix
authors.affiliation: Institut des Sciences Moléculaires d'Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pino
authors.affiliation: Institut des Sciences Moléculaires d'Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Pirali
authors.affiliation: INAF - Osservatorio Astronomico di Cagliari, via della scienza 5, I-09047 Selargius (CA), Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Mulas
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Nahon