Molecules in the early universe

Journal Article · Tue May 15 04:00:00 EDT 1984 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/162013· OSTI ID:6344368

Lepp, S; Shull, J M

We present calculations of the formation of astrophysically interesting molecules (H/sub 2/, HD, LiH, and HeH/sup +/) by gas-phase reactions during the postrecombination epoch (redshifts z = 300-30). In standard Friedmann cosmological models, H/sub 2//Hroughly-equal10/sup -6/, HD/H/sub 2/roughly-equal10/sup -4.5/, and LiH/H/sub 2/roughly-equal10/sup -6.5/. These molecules may dominate the cooling and trigger the collapse of primordial gas clouds. The dipole rotational transitions of HD and LiH are particularly important at high density and low temperature. Additional molecules form during spherical collapse of these clouds, their rotational cooling keeps the gas temperature between 400 and 1500 K over 12 decades of density increase until the H/sub 2/ lines become optically thick. The existence of molecular coolants at high redshift has significant implications for the first generation of stars and for thermal instabilities in intergalactic matter.

• Research Organization: Department of Physics, University of Colorado
• OSTI ID: 6344368
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 280:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640106* -- Astrophysics & Cosmology-- Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKALI METAL COMPOUNDS
CHEMISTRY
COLLISIONS
COOLING
COSMIC GASES
COSMOCHEMISTRY
COSMOLOGICAL MODELS
COSMOLOGY
DENSITY
DEUTERIUM
ELEMENTS
FLUIDS
GASES
HELIUM COMPOUNDS
HELIUM HYDRIDES
HIGH TEMPERATURE
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INSTABILITY
ISOTOPES
LIGHT NUCLEI
LITHIUM COMPOUNDS
LITHIUM HYDRIDES
MATHEMATICAL MODELS
MOLECULES
MOTION
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OPACITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
POLYATOMIC MOLECULES
PROTOSTARS
RARE GAS COMPOUNDS
RECOMBINATION
ROTATION
STABLE ISOTOPES
UNIVERSE
VERY HIGH TEMPERATURE