Large molecules in diffuse interstellar clouds

Journal Article · Wed Jun 01 04:00:00 EDT 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166388· OSTI ID:6854913

Lepp, S; Dalgarno, A; Van Dishoeck, E F; Black, J H

The effects of the presence of a substantial component of large molecules on the chemistry of diffuse molecular clouds are explored, and detailed models of the zeta Persei and zeta Ophiuchi clouds are constructed. The major consequence is a reduction in the abundances of singly charged atomic species. The long-standing discrepancy between cloud densities inferred from rotational and fine-structure level populations and from the ionization balance can be resolved by postulating a fractional abundance of large molecules of 1 x 10 to the -7th for zeta Persei and 6 x 10 to the -7th for zeta Ophiuchi. If the large molecules are polycyclic aromatic hydrocarbons (PAH) containing about 50 carbon atoms, they contain 1 percent of the carbon in zeta Persei and 7 percent in zeta Ophiuchi. Other consequences of the possible presence of PAH molecules are discussed. 23 references.

• Research Organization: Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA); Princeton Univ. Observatory, NJ (USA); Steward Observatory, Tucson, AZ (USA)
• OSTI ID: 6854913
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 329; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHEMICAL COMPOSITION
CHEMISTRY
COSMIC GASES
COSMOCHEMISTRY
FLUIDS
GASES
HYDROCARBONS
INTERSTELLAR SPACE
IONIZATION
KINETICS
MOLECULES
ORGANIC COMPOUNDS
REACTION KINETICS
SPACE