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Electron impact dissociative excitation of O2: 2. Absolute emission cross sections of the OI(130.4 nm) and OI(135.6 nm) lines
- Source :
- Journal of Geophysical Research. 108
- Publication Year :
- 2003
- Publisher :
- American Geophysical Union (AGU), 2003.
-
Abstract
- [1] In this work, we report the OI(135.6 nm) absolute emission cross section resulting from the long-lived (180 μs) OI(5S → 3P) transition from dissociative excitation of O2. From the ratio of the integrated intensities of the OI(135.6 nm) and OI(130.4 nm) features and from the absolute emission cross section for the OI(130.4 nm) emission feature from electron impact dissociative excitation of O2 at 100 eV, the absolute emission cross section for the OI(135.6 nm) feature was determined to be 6.4 × 10−18 cm2 at 100 eV. Electron impact-induced optical excitation functions for optically allowed transitions at 115.2 nm and 130.4 nm and for an optically forbidden transition at 135.6 nm were also obtained over the electron impact energy range 0–600 eV. The OI(135.6 nm) emission cross section was measured in the laboratory utilizing a large collision chamber (1.5 m in diameter). Electrons were produced with an electrostatically focusing gun with a large focal length (50 cm). The OI(130.4 nm, 135.6 nm) excitation functions were put on an absolute scale as described in the text, and the OI(135.6 nm)/OI(130.4 nm) ratio was determined for the entire energy range (0–600 eV). The atomic O UV emission cross sections from dissociative excitation of O2 can be used to model the recent Hubble Space Telescope observations of OI(130.4 nm) and OI(135.6 nm) intensities from Ganymede [Feldman et al., 2000] and Europa [Hall et al., 1995, 1998].
- Subjects :
- Excitation function
Atmospheric Science
Range (particle radiation)
Materials science
Ecology
Paleontology
Soil Science
Forestry
Electron
Aquatic Science
Oceanography
Cross section (geometry)
Geophysics
Space and Planetary Science
Geochemistry and Petrology
Hubble space telescope
Earth and Planetary Sciences (miscellaneous)
Atomic physics
Absolute scale
Electron ionization
Excitation
Earth-Surface Processes
Water Science and Technology
Subjects
Details
- ISSN :
- 01480227
- Volume :
- 108
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research
- Accession number :
- edsair.doi...........0874b6d7f1b4da7bb391d464c987864d