Absolute differential and integral electron excitation cross sections for atomic nitrogen. 1. The sup 4 S degree yields 3s sup 4 P (. lambda. 1200 angstrom ) transition from 30 to 100 eV
- Johns Hopkins Univ., Baltimore, MD (United States)
The absolute direct differential and integral electron excitation cross sections for the atomic nitrogen {sup 4}S{degree} {yields} 3s{sup 4}P ({lambda}1200 {angstrom}) transition have been measured at incident energies of 30, 50, and 100 eV. The differential cross sections (DCS) measured versus scattering angle were integrated to give the integral cross section (ICS) as a function of incident energy. The ICS has a maximum value of 66 {times} 10{sup {minus}18} cm{sup 2} near 50 eV. Above 50 eV, the direct excitation cross section is approximately a factor of two lower than fluorescence cross section of Sone and Zipf when the latter is corrected for the recent change in the H{sub 2} dissociative excitation reference cross section. This difference suggests that cascade accounts for {approximately}50% of the fluorescence emission above 50 eV. At 30 eV, the direct cross section is only 1/5 of the fluorescence cross section, suggesting that there is a strong cascade contribution to the fluorescence cross section from forbidden transitions to the 3p {sup 4}D{degree} and 3p {sup 4}P{degree} states just above threshold. The consequences of these new cross section values for aeronomy are discussed.
- OSTI ID:
- 5221501
- Journal Information:
- Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A9; ISSN 0148-0227; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRGLOW
ATOM COLLISIONS
AURORAE
COLLISIONS
CROSS SECTIONS
DATA
DIFFERENTIAL CROSS SECTIONS
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
ELEMENTS
EMISSION SPECTRA
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 10-100
EXCITATION
EXPERIMENTAL DATA
FLUORESCENCE
INFORMATION
INTEGRAL CROSS SECTIONS
LUMINESCENCE
NITROGEN
NONMETALS
NUMERICAL DATA
SPECTRA