title: Interaction of atomic and molecular hydrogen with tholin surfaces at low temperatures.
abstract: We study the interaction of atomic and molecular hydrogen with a surface of tholin, a man-made polymer considered to be an analogue of aerosol particles present in Titan's atmosphere, using thermal programmed desorption at low temperatures below 30 K. The results are fitted and analyzed using a fine-grained rate equation model that describes the diffusion, reaction, and desorption processes. We obtain the energy barriers for diffusion and desorption of atomic and molecular hydrogen. These barriers are found to be in the range of 30-60 meV, indicating that atom/molecule-surface interactions in this temperature range are dominated by weak adsorption forces. The implications of these results for the understanding of the atmospheric chemistry of Titan are discussed.
authors.affiliation: Physics Department, Syracuse University, Syracuse, New York 13244, USA.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Vidali
authors.forename: Yechiel
authors.initials: Y
authors.lastname: Frank
authors.forename: Ingo
authors.initials: I
authors.lastname: Lohmar
authors.forename: Hagai B
authors.initials: HB
authors.lastname: Perets
authors.forename: Ofer
authors.initials: O
authors.lastname: Biham
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D000336:Aerosols; D006859:Hydrogen