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Emission cross section of O I (135.6 nm) at 100 eV resulting from electron‐impact dissociative excitation of O 2
Author(s) -
Noren C.,
Kanik I.,
Ajello J. M.,
McCartney P.,
Makarov O. P.,
McClintock W. E.,
Drake V. A.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012577
Subject(s) - excitation , atomic physics , electron ionization , physics , electron , cross section (physics) , electron capture , analytical chemistry (journal) , ionization , chemistry , ion , nuclear physics , chromatography , quantum mechanics
In this Letter, we report for the first time, the ratio of the O I (135.6 nm)/O I (130.4 nm) absolute emission cross sections from electron‐impact dissociative excitation of O 2 at 100 eV using facilities located at the University of Colorado, Laboratory for Atmospheric and Space Physics (LASP). The O I (135.6 nm) emission glow produced in the laboratory from the long‐lived transition O I g ³P ← 5 S° was measured in a large collision chamber (1m diameter) with a long focal length (50 cm) electrostatic electron gun. The ratio of the absolute emission cross sections of the O I (135.6 nm) and O I (130.4 nm) features resulting from electron‐impact dissociative excitation of O 2 at 100 eV was found to be 2.3±0.6. From this ratio, the absolute emission cross section for the O I (135.6 nm) feature at 100 eV electron‐impact energy was determined to be (6.4±2.2)×10 −18 cm². The O I (135.6 nm) cross section reported here can be used to better understand the recent Hubble Space Telescope observations of the O I (130.4 nm) and O I (135.6 nm) emission intensities from Ganymede [ Feldman et al., 2000] and Europa [ Hall et al., 1995].