Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
The formation of isomers as potential key intermediates C5H5 to polycyclicaromatic hydrocarbon-like molecules
Autore:
Kaiser, RI; Lee, HY; Mebel, AM; Lee, YT;
Indirizzi:
Tech Univ Chemnitz, Dept Phys, D-09107 Chemnitz, Germany Tech Univ Chemnitz Chemnitz Germany D-09107 s, D-09107 Chemnitz, Germany Natl Taiwan Univ, Dept Phys, Taipei 106, Taiwan Natl Taiwan Univ Taipei Taiwan 106 n Univ, Dept Phys, Taipei 106, Taiwan Natl Taiwan Univ, Dept Chem, Taipei 106, Taiwan Natl Taiwan Univ Taipei Taiwan 106 n Univ, Dept Chem, Taipei 106, Taiwan
Titolo Testata:
ASTROPHYSICAL JOURNAL
fascicolo: 2, volume: 548, anno: 2001,
parte:, 1
pagine: 852 - 860
SICI:
0004-637X(20010220)548:2<852:TFOIAP>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
CROSSED-BEAM REACTION; CHEMICAL-DYNAMICS; CARBON-ATOMS; INFRARED-SPECTROSCOPY; RADICAL FORMATION; C(P-3(J)); CATIONS; MODEL; PAHS; C6D6(X(1)A(1G));
Keywords:
ISM : molecules; methods : laboratory; molecular processes;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Kaiser, RI Inst Atom & Mol Sci, 1 Sect,4 Roosevelt Rd, Taipei 106, Taiwan Inst Atom & Mol Sci 1 Sect,4 Roosevelt Rd Taipei Taiwan 106 an
Citazione:
R.I. Kaiser et al., "The formation of isomers as potential key intermediates C5H5 to polycyclicaromatic hydrocarbon-like molecules", ASTROPHYS J, 548(2), 2001, pp. 852-860

Abstract

The reactions of ground-state atomic carbon with three C4H6 isomers, dimethylacetylene, 1,2- butadiene, and 1,3-butadiene, are studied at relative collision energies between 19.3 and 48.6 kJ mol(-1) in crossed molecular beamexperiments to elucidate the reaction products and chemical dynamics to form C5H5 isomers-possible precursor radicals to PAH-like species-in the circumstellar envelopes of carbon-rich asymptotic giant branch (AGB) stars. Ourcombined experimental and computational studies show that reactions are dominated by the C(P-3(j)) versus hydrogen atom exchange to form the 1-methylbutatrienyl radical, H2CCCCCH3 (X(2)A"), as well as 1- and 3-vinylpropargylradicals, HCCCHC2H3 (X(2)A") and H2CCCC2H3 (X(2)A"), under single-collision conditions. The methyl (CH3) and vinyl radical (C2H3) loss channels to yield the propargyl radical C3H3 ((XB2)-B-2) and n-C4H3 (X(2)A') are only minor pathways. All reactions have no entrance barrier and are dominated by anaddition of the carbon atom to the pi electron density of the second reactant via a complex-forming reaction mechanism on the triplet potential energy surface (PES). The decomposing complexes are long lived and reside in a deep potential energy well bound by 360-410 kJ mol(-1) with respect to the separated reactants. Tight exit transition states of about 20 kJ mol(-1) above the products and strong exothermic reactions of 180-240 kJ mol(-1) are common features of the involved PESs. These characteristics make the reactions of atomic carbon with C4H6 isomers a compelling candidate to form C5H5 isomers in the outflow of AGB stars.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/04/20 alle ore 20:57:47