A study of electron impact excitation of NO: The middle ultraviolet from 170 to 270 nm
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena (US)
- Physics Department, Manchester University, Manchester, England
The electron impact induced fluorescence spectrum of NO at 200 eV has been studied from 170 to 270 nm in a crossed beam experiment. By modeling the laboratory spectrum, including the effects of spin-orbit splitting of the ground state, we determined the emission cross sections of the {gamma}({ital A}{sup 2}{Sigma+}{r arrow} {ital X2}{Pi}{sub {ital r}}) and {var epsilon} ({ital D}{sup 2}{Sigma+}{r arrow}{ital X2}{Pi}{sub {ital r}}) band systems. The emission cross section of the {gamma} bands includes a large cascade cross-section contribution from high lying Rydberg states that predominantly populate the {ital v}{prime}=0 level of the {ital A}{sup 2}{Sigma+} state. The {var epsilon} bands are modeled by excitation rates proportional to Franck-Condon factors for direct excitation. One feature is tentatively identifed as the (1,0) {delta} band and permits an estimate of the ({ital C}{sup 2}{Pi}{sub {ital r}} {ital v}{prime}{minus}1{r arrow}{ital X}{sup 2}{Pi}{sub {ital r}} {ital v}=0) emission cross section. Previous low-resloution emission studies of electron impact excitation of the {gamma} bands have not taken into account the heavy spectral blending by the {delta} , {var epsilon}, and {Beta}{prime} bands. A major result of this study indicates great care hdas to be used if NO is taken as a target for relative calibration in the middle ultraviolet (MUV) using the molecular branching ratio technique. The identification of all features in the MUV spectrum allow aeronomers to identify emission features that may arise from electron impact excitation and other chemical processes occurring in the upper atmospheres of the inner planets where NO is a constituent. {copyright} American Geophysical Union 1989
- OSTI ID:
- 5593776
- Journal Information:
- Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A7; ISSN 0148-0227; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATMOSPHERES
CHALCOGENIDES
CHEMICAL COMPOSITION
COLLISIONS
COUPLING
CROSS SECTIONS
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ENERGY LEVELS
ENERGY RANGE
EV RANGE
EV RANGE 100-1000
EXCITED STATES
FLUORESCENCE
INTERMEDIATE COUPLING
L-S COUPLING
LUMINESCENCE
MOLECULE COLLISIONS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PLANETARY ATMOSPHERES
RYDBERG STATES
SPECTRA
ULTRAVIOLET SPECTRA