Title: | Molecular Isomer Identification of Titan's Tholins Organic Aerosols by Photoelectron/Photoion Coincidence Spectroscopy Coupled to VUV Synchrotron Radiation |
Author(s): | Cunha de Miranda B; Garcia GA; Gaie-Levrel F; Mahjoub A; Gautier T; Fleury B; Nahon L; Pernot P; Carrasco N; |
Address: | "Synchrotron SOLEIL, DESIRS Beamline , L'Orme des Merisiers, St Aubin, 91192 Gif-sur-Yvette Cedex, France. Gas and Aerosol Metrology Department, Chemistry and Biology Division, Laboratoire National de Metrologie et d'Essais - LNE (National Metrology Institute and Testing Laboratory) , 1 rue Gaston Boissier, 75724 Paris Cedex 15, France. Universite Versailles St-Quentin; Sorbonne Universites, UPMC Universite Paris 06, CNRS/INSU, LATMOS-IPSL , 11 Boulevard d'Alembert, 78280 Guyancourt, France. NASA Postdoctoral Program, GSFC , Greenbelt, Maryland 20771, United States. Laboratoire de Chimie Physique, UMR8000 CNRS/Universite Paris-Sud , 91405 Orsay Cedex, France. Institut Universitaire de France , 103 Boulevard St-Michel, 75005 Paris, France" |
ISSN/ISBN: | 1520-5215 (Electronic) 1089-5639 (Linking) |
Abstract: | "The chemical composition of Titan organic haze is poorly known. To address this issue, laboratory analogues named tholins are synthesized and analyzed by methods often requiring an extraction process in a carrier solvent. These methods exclude the analysis of the insoluble tholins' fraction and assume a hypothetical chemical equivalence between soluble and insoluble fractions. In this work, we present a powerful complementary analysis method recently developed on the DESIRS VUV synchrotron beamline at SOLEIL. It involves soft pyrolysis of tholins at approximately 230 degrees C and electron/ion coincidence analysis of the emitted volatile compounds photoionized by tunable synchrotron radiation. By comparison with reference photoelectron spectra (PES), the spectral information collected on the detected molecules yields their isomeric structure. The method is more readily applied to light species (m/z = 69), while for heavier ones, the number of possibilities and the lack of PES reference spectra in the literature limit its analysis. A notable pattern in the analyzed tholins is the presence of species containing adjacent doubly bonded N atoms, which might be a signature of heterogeneous incorporation of N2 in tholins" |
Notes: | "PubMed-not-MEDLINECunha de Miranda, Barbara Garcia, Gustavo A Gaie-Levrel, Francois Mahjoub, Ahmed Gautier, Thomas Fleury, Benjamin Nahon, Laurent Pernot, Pascal Carrasco, Nathalie eng 2016/07/30 J Phys Chem A. 2016 Aug 25; 120(33):6529-40. doi: 10.1021/acs.jpca.6b03346. Epub 2016 Aug 12" |