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Linewidth studies on the the NI(4S-4P) resonance multipletDoppler broadening of the 8691, 8212, and 1200-A multiplet lines of N I is investigated experimentally, and its implications for the interpretation of the earth's 1200-A UV dayglow are considered. A regulated 100-eV, 1-mA electron beam is passed through N2 at 300 K and about 0.0005 torr flowing through a collision chamber within a UHV system, and the radiation emitted is observed with a temperature-stabilized short-focal length monochromator with a bandpass of 0.2 A in the IR and an effective UV resolution (in second-order operation with a 3600-groove/mm plane grating) of about 0.04 A. Both the IR and VUV lines are found to be broadened to about 25 times the thermal Doppler linewidth, with the IR transitions accounting for more than half of the total N(4P) cross section at 100 eV. The kinetic energy of the N(4P) atoms produced by dissociative excitation is such that their 1200-A resonance radiation (2p2 3s4P - 2p3 4SO) would be optically thin in the upper atmosphere, contrary to what has been observed. A need to revise some aspects of current UV-dayglow models is identified.
Document ID
19840030768
Document Type
Reprint (Version printed in journal)
Authors
Erdman, P. W. (Pittsburgh Univ. Pittsburgh, PA, United States)
Zipf, E. C. (Pittsburgh, University Pittsburgh, PA, United States)
Date Acquired
August 12, 2013
Publication Date
November 1, 1983
Publication Information
Publication: Planetary and Space Science
Volume: 31
ISSN: 0032-0633
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NGL-39-011-030
CONTRACT_GRANT: NSF ATM-81-07145
Distribution Limits
Public
Copyright
Other