Model for diffuse interstellar clouds: improvements to the theory of molecular hydrogen photodestruction and to the gas phase chemistry of carbon monoxide

Thesis/Dissertation · Mon Jan 01 00:00:00 EST 1979

OSTI ID:5671294

Federman, S R

A theoretical model has been developed to determine physical processes in conjunction with astrophysical observation. The calculations are based on isobaric, steady-state, plane-parallel conditions. In the model, the cloud is illuminated by ultraviolet radiation from one side. The density and temperature of the gas are derived by invoking energy conservation in terms of thermal balance. The derived values for density and temperature then are used to determine the abundances of approximately fifty atomic and molecular species, including important ionic species and simple carbon and oxygen bearing molecules. Except for molecular hydrogen formation on dust grains, binary gas phase reactions are used to develop the chemistry of the model cloud. The theoretical model has been found to be appropriate for a particular range of physical parameters. The results of the steady-state calculations have been compared to ultraviolet observations, predominantly those made with the Copernicus satellite. The theory of molecular hydrogen photodestruction has been reexamined so that improvements to the model can be made. By analyzing the region where the atomic to molecuar hydrogen transition occurs, several processes have been found to contribute to dissociation.

• Research Organization: New York Univ., NY (USA)
• OSTI ID: 5671294
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
MATHEMATICAL MODELS
ATOMS
CARBON
CARBON MONOXIDE
CHARGE EXCHANGE
CHEMICAL COMPOSITION
COSMOCHEMISTRY
DENSITY
DISSOCIATION
HYDROGEN
LYMAN LINES
MOLECULES
SATELLITES
TEMPERATURE MEASUREMENT
ULTRAVIOLET RADIATION
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMISTRY
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GASES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
640105* - Astrophysics & Cosmology- Galaxies