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Titolo:
THE RADIATIVE ASSOCIATION OF CH WITH H-2 - A MECHANISM FOR FORMATION OF CH3 IN INTERSTELLAR CLOUDS
Autore:
BROWNSWORD RA; SIMS IR; SMITH IWM; STEWART DWA; CANOSA A; ROWE BR;
Indirizzi:
UNIV BIRMINGHAM,SCH CHEM,POB 363 BIRMINGHAM B15 2TT W MIDLANDS ENGLAND UNIV RENNES 1,EQUIPE ASTROCHIM EXPT,UNITE MIXTE RECH 6627,CNRS F-35042 RENNES FRANCE
Titolo Testata:
The Astrophysical journal
fascicolo: 1, volume: 485, anno: 1997,
parte:, 1
pagine: 195 - 202
SICI:
0004-637X(1997)485:1<195:TRAOCW>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
NEUTRAL-NEUTRAL REACTIONS; ION-MOLECULE ASSOCIATION; TRANSITION DIPOLE-MOMENT; 13 K; COLLISIONS; CHEMISTRY; CH-3+;
Keywords:
ISM, ABUNDANCE; ISM, MOLECULES; MOLECULAR PROCESSES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
43
Recensione:
Indirizzi per estratti:
Citazione:
R.A. Brownsword et al., "THE RADIATIVE ASSOCIATION OF CH WITH H-2 - A MECHANISM FOR FORMATION OF CH3 IN INTERSTELLAR CLOUDS", The Astrophysical journal, 485(1), 1997, pp. 195-202

Abstract

Estimates of the rate constants for the radiative association of methylidene radicals (CH) with molecular hydrogen (H-2), CH + H-2 --> CH3 hv, are reported for the temperature range (10-100 K) prevalent in dense interstellar clouds. These estimates are based on (1) new and extensive laboratory experiments on the collisional association of CH andH-2, CH + H-2(+M) --> CH3(+M), including measurements of rate constants down to temperatures as low as 53 K; and (2) calculations of the rate constants for both radiative and collisional association based on methods originally proposed by Troe, modified to include the effects ofquantum mechanical tunneling as proposed by Smith. The results suggest that radiative association of CH with H-2 may be a significant reaction in interstellar clouds because of the high abundance of H-2. Although the association of CH with H-2 seems likely to be only a minor route for the removal of CH radicals, the reaction does provide a pathwayto the formation of CH3, and subsequently simple hydrocarbons, which may be of comparable importance to other mechanisms based on ion-molecule chemistry. In addition, measured and estimated low temperature rate coefficients are reported for isotope exchange between CH, CD and H-2, HD, D-2 which may be relevant to isotopic fractionation in interstellar clouds.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 18:29:38