Photodissociation of the Diacetylene Dimer and Implications for Hydrocarbon Growth in Titan's Atmosphere

On the Radiolysis of Ethylene Ices by Energetic Electrons and Implications to the Extraterrestrial Hydrocarbon Chemistry

“…The fits suggest that an ethylene dimer complex undergoes an intramolecular hydrogen transfer to an ethyl (C 2 H 5 ) radical plus a vinyl radical (C 2 H 3 ). Intramolecular hydrogen transfer processes are initiated in dimers of, for instance, hydrocarbons like diacetylene ((C 4 H 2 ) 2 ) upon pho- tolysis at Lyα (Huang et al 2010). A second hydrogen transfer reduces the ethyl (C 2 H 5 ) radical to ethane (C 2 H 6 ; k 4 = 1.2 ± 0.2 × 10 −3 s −1 ).…”

Molecular growth upon ionization of van der Waals clusters containing HCCH and HCN is a pathway to prebiotic molecules

“…Molecular growth from dimers of acetylene and higher annulenes have indeed been proposed for Titan's atmosphere. 53 In this manuscript, we present an AIMD and quantum chemistry study of the formation routes of different nitrogenated cyclic molecules starting from clusters of pure HCN, and mixed clusters of HCN and HCCH, upon ionization. Our results will address whether an analogous mechanism can account for the formation of the radical cations of the basic building blocks of life, namely pyridine, pyrimidine, and triazine, in a fashion similar to the formation of benzene radical cation previously seen in a joint laboratory and theoretical study.…”

Indene Formation under Single‐Collision Conditions from the Reaction of Phenyl Radicals with Allene and Methylacetylene—A Crossed Molecular Beam and Ab Initio Study

“…Soot from fossil fuel combustion is widely accepted as causing detrimental effects to health and the environment, such as being carcinogenic and mutagenic, as well as contributing to global warming. [1][2][3] Soot is thought to be formed in a stepwise molecular-weight growth process, leading from small hydrocarbons and their C2, C3, and C4 radicals, such as ethynyl (C 2 H) [4] and propargyl (C 3 H 3 ), [5] to aromatic molecules, such as benzene (C 6 H 6 ) and the phenyl radical (C 6 H 5 ), followed by the formation of polycyclic aromatic hydrocarbons (PAHs) and eventually particulate matter (soot). [6][7][8][9] The first step, the formation of the first aromatic ring structure (benzene and/or the phenyl radical), has been proposed through self-reaction of the propargyl radical, [7,[9][10][11][12][13][14][15][16][17][18] and more recently via the reactions of dicarbon (C 2 ) [19] and ethynyl radicals (C 2 H) [4] with 1,3-butadiene (C 4 H 6 ).…”

“…At combustion temperatures between 1000 and 2000 K and at pressures of 1 to 100 atm, indene plus a hydrogen atom was found to account for only 5 % of the products, although Vereecken et al admitted this was subject to major errors owing to the branching ratios being sensitive to collisional transfer processes, especially for stabilized versus dissociated products. Because 5 ]phenyl radical (C 6 D 5 X 2 A 1 ) with [D 4 ]allene (D 2 CCCD 2 X 1 A 1 ) monitored at m/z 124. Bottom: TOF data for the reaction of the [D 5 ]phenyl radical (C 6 D 5 X 2 A 1 ) with [D 4 ]methyl acetylene (CD 3 CCD X 1 A 1 ) monitored at m/z 124. no experimental data existed at that time, there was no way to calibrate these parameters effectively.…”