Absolute experimental differential and integral electron excitation cross sections for atomic oxygen. 3. The ( sup 3 P yields sup 3 D degree ) transition (989 angstrom ) from 20 to 200 eV with improved values for the ( sup 3 P yields sup 3 S degree ) transition (1,304 angstrom )

Journal Article · Wed Jul 01 00:00:00 EDT 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA07p07749· OSTI ID:5398419

Vaughan, S O; Doering, J P ^[1]

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1. Johns Hopkins Univ., Baltimore, MD (United States)

The absolute differential and integral electron excitation cross sections for the atomic oxygen {sup 3}P {yields} {sup 3}D {degree} transition (989 {angstrom}) have been measured at incident energies from 20 to 200 eV. A variable angle and incident energy electron spectrometer coupled to a microwave discharge free supersonic jet expansion source was used for the experiments. The source produced an O/O{sub 2} density ratio typically greater than 2.5. The differential cross sections were determined by comparison to computer-fitted recalculations of the differential cross section for the atomic oxygen {sup 3}P {yields} {sup 3}S {degree} transition (1,304 {angstrom}). The method used for the computer fit and the results of the fitting calculations are discussed for the {sup 3}P {yields} {sup 3}S {degree} atomic oxygen transition (1,304 {angstrom}). The O I {sup 3}P {yields}{sup 3}S {degree} (989 {angstrom}) differential cross sections vary smoothly with the incident energy and are flatter with scattering angle at the lower incident energies, as expected. The absolute integral cross section is found to agree with the theoretical shape at higher energies. Previous estimates of this cross section from fluorescence data were larger than the present values by approximately a factor of 2. The present lower value appears to provide much better agreement with aurora and dayglow 989 {angstrom} emission intensities.

• OSTI ID: 5398419
• Journal Information: Journal of Geophysical Research; (United States), Vol. 92:A7; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRGLOW
EMISSION SPECTRA
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ELECTRON-ATOM COLLISIONS
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OXYGEN
COMPARATIVE EVALUATIONS
DIFFERENTIAL CROSS SECTIONS
EV RANGE 10-100
EV RANGE 100-1000
INTEGRAL CROSS SECTIONS
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
ELECTRON COLLISIONS
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EVALUATION
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