Isotope-selective photodestruction of carbon monoxide

Journal Article · Thu Apr 01 04:00:00 EST 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159812· OSTI ID:5129295

Bally, J; Langer, W D

Observations of the molecular cloud boundary layer near the H II region S68 reveal an over-abundance of /sup 12/CO and /sup 13/CO relative to C/sup 18/O consistent with a simple model of isotope-selective photodestruction of the rarer CO species. Self-shielding and the isotopic shift of the UV dissociative transitions increase the lifetime of the more abundant isotopes of carbon monoxide in a UV irradiated environment. As a result, large variations occur in the abundance ratios of CO isotopes in the surface layer of clouds and near internal UV sources. This effect is important for the determination of molecular abundances, cloud masses, isotope ratios, and molecular excitation conditions.

• Research Organization: Crawford Hill Laboratory, Bell Laboratories, Holmdel, New Jersey
• OSTI ID: 5129295
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 255:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
BOUNDARY LAYERS
CARBON 12
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
H2 REGIONS
ISOTOPE RATIO
ISOTOPES
LAYERS
LIGHT NUCLEI
MOLECULES
NEBULAE
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
STABLE ISOTOPES
ULTRAVIOLET RADIATION