MECHANISTICAL STUDIES ON THE FORMATION AND NATURE OF THE 'XCN' (OCN{sup -}) SPECIES IN INTERSTELLAR ICES

Journal Article · Mon Nov 01 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/723/1/641· OSTI ID:21467168

Bennett, C J; Jones, B; Knox, E; Perry, J; Kim, Y S

We conducted laboratory experiments on the interaction of ionizing radiation in the form of energetic electrons with interstellar model ices to investigate the nature and possible routes to form the 'XCN' species as observed at 4.62 {mu}m (2164 cm{sup -1}) in the interstellar medium. Our laboratory experiments provided compelling evidence that the isocyanide ion (OCN{sup -}) presents the carrier of the 'XCN' feature in interstellar ices. Most importantly, the studies exposed-based on kinetic fits of the temporal profiles of important reactants, intermediates, and products-that two formation mechanisms can lead to the production of the isocyanide ion (OCN{sup -}) in low-temperature interstellar ices. In carbon monoxide-ammonia ices, unimolecular decomposition of ammonia leads to reactive NH{sub 2} and NH radical species, which in turn can react with neighboring carbon monoxide to form ultimately the isocyanide ion (OCN{sup -}); this process also involves a fast proton transfer to a base molecule in the surrounding ice. Second, cyanide ions (CN{sup -})-formed via unimolecular decomposition of methylamine (CH{sub 3}NH{sub 2}) via a methanimine (CH{sub 2}NH) intermediate-can react with suprathermal oxygen atoms forming the isocyanide ion (OCN{sup -}). We also discuss that the isocyanide ion (OCN{sup -}) can be used as a molecular tracer to determine, for instance, the development stage of young stellar objects and also the chemical history of ices processed by ionizing radiation.

• OSTI ID: 21467168
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 723; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMINES
AMMONIA
ASTROPHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COMETS
COSMIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HYDRIDES
HYDROGEN COMPOUNDS
ICE
IONIZING RADIATIONS
IONS
LEPTONS
METHYLAMINE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICS
RADIATIONS
TAIL ELECTRONS