Translational and rotational energy of hydrogen molecules after recombination on interstellar grains

Journal Article · Thu Nov 30 23:00:00 EST 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156630· OSTI ID:6364389

Hunter, D A; Watson, W D

Trajectories based on classical mechanics are computed for recombining H/sub 2/ molecules on rigid surfaces. Monte Carlo sampling of initial locations and velocities is utilized to obtain the average translational energy per molecule formed and the average rotational state of the molecules that escape. Various values for the adsorption energy are considered. In the limit of pure physical adsorption, the average translational energy is about 0.2 eV and the average rotational state is greater than J=7. Since transfer of energy into the surface is not included, the calculations here are expected to yield upper limits to the actual energies after recombination on interstellar dust grains. For adsorption energies which we regard as likely for hydrogen on interstellar grains, our calculations indicate that heating of the gas in interstellar clouds by energy from H/sub 2/ recombination is less significant than might be supposed. The calculations do support the proposal that recombination contributes to the observed abundances of H/sub 2/ molecules in the J> or approx. =4 states.

• Research Organization: Departments of Physics and Astronomy, University of Illinois at Urbana-Champaign
• OSTI ID: 6364389
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 226:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CLASSICAL MECHANICS
COSMIC DUST
COSMIC GASES
CRYOGENIC FLUIDS
DUSTS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
HYDROGEN
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
MECHANICS
MOLECULES
MONTE CARLO METHOD
NONMETALS
PARTICLES
RECOMBINATION
ROTATIONAL STATES
SPACE