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Title: Photoionization of cold gas phase coronene and its clusters: Autoionization resonances in monomer, dimer, and trimer and electronic structure of monomer cation

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:
; ; ; ;  [1] ; ;  [2] ; ; ;  [3] ;  [4]
  1. Institut des Sciences Moléculaires d’Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay (France)
  2. Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette (France)
  3. IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4 (France)
  4. INAF - Osservatorio Astronomico di Cagliari, via della scienza 5, I-09047 Selargius (Italy)
Publication Date:
OSTI Identifier:
22311336
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ABSORPTION SPECTROSCOPY; AUTOIONIZATION; CATIONS; DENSITY FUNCTIONAL METHOD; DETECTION; DIMERS; ELECTRONIC STRUCTURE; MOLECULAR BEAMS; MOLECULES; MONOMERS; PHOTOIONIZATION; PHOTONS; POLYCYCLIC AROMATIC HYDROCARBONS; SPECTRA