Cross Sections for Emission of Lyman-Alpha Radiation in Collisions of 1-25 keV Protons and Hydrogen Atoms with Constituents of Planetary Atmospheres.
Rept. for Jul-Nov 71,
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
Pagination or Media Count:
Cross sections are reported for emission of Lyman-alpha radiation in collisions of a charge-equilibrated 1-25 keV hydrogen beam with N2, O2, CO, CO2, NH3, CH4, and H2. For each target molecule, the separate cross sections for formation of H2p and H2s in H and H collisions and the fractional population of these projectiles in a charge-equilibrated beam are used to calculate the effective cross section for formation of H2p and H2s. Individual contributions to the overall Lyman-alpha intensity owing to projectile and dissociative excitation are presented for the hydrogen-containing compounds. The results show that, for both projectile and dissociative excitation, collisions involving impact of fast hydrogen atoms rather than protons are the major source of Lyman-alpha production in an aurora. Projectile excitation is demonstrated to be a substantially more important source of Lyman alpha than dissociative excitation in the 1-25 keV energy range. Author
- Atmospheric Physics
- Atomic and Molecular Physics and Spectroscopy