Deuterium fractionation mechanisms in interstellar clouds

Journal Article · Sat Dec 01 04:00:00 EST 1984 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/184395· OSTI ID:5992633

Dalgarno, A; Lepp, S

The theory of the fractionation of deuterated molecules is extended to include reactions with atomic deuterium. With the recognition that dissociative recombination of H/sup +//sub 3/ is not rapid, observational data can be used in conjunction with the theory to derive upper and lower bounds to the cosmic deuterium-hydrogen abundance ratio. We find that (D)/(H) is at least 3.4 x 10/sup -6/ and at most 4.0 x 10/sup -5/ with a probable value of 1 x 10/sup -5/. Because of the reaction HCO/sup +/+D..-->..DCO/sup +/+H, upper limits can be derived for the fractional ionization which depend only weakly on the cosmic ray flux, zeta. In four clouds, the upper limits to the fractional ionization lie between 1.1 x 10/sup -6/ and 1.5 x 10/sup -6/ if zeta = 10/sup -7/ s/sup -1/ and between 3.1 x 10/sup -6/ and 1.8 x 10/sup -6/ if zeta = 10/sup -16/ s/sup -1/.

• Research Organization: Harvard-Smithsonian Center for Astrophysics
• OSTI ID: 5992633
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 287:1; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHARGED PARTICLES
CHEMICAL REACTIONS
COSMIC RADIATION
DEUTERIUM
DEUTERIUM IONS
ELEMENTS
HYDROGEN
HYDROGEN ISOTOPES
INTERSTELLAR GRAINS
IONIZATION
IONIZING RADIATIONS
IONS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PARTICLES
RADIATION FLUX
RADIATIONS
STABLE ISOTOPES