Electron-impact excitation of the second positive band system ({ital C}{sup 3}{Pi}{sub {ital u}}{r_arrow}{ital B}{sup 3}{Pi}{sub {ital g}}) and the {ital C}{sup 3}{Pi}{sub {ital u}} electronic state of the nitrogen molecule

Journal Article · Mon Apr 01 00:00:00 EST 1996 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.53.2239· OSTI ID:279911

Fons, J T; Schappe, R S; Lin, C C ^[1]

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1. Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

Absolute optical emission cross sections have been measured for the second-positive band system of N{sub 2}, {ital C}{sup 3}{Pi}{sub {ital u}}({ital v}{prime}){r_arrow}{ital B}{sup 3}{Pi}{sub {ital g}}({ital v}{double_prime}), for {ital v}{prime}=0,1,2,3,4 and {ital v}{double_prime} as large as 9 produced by electron impact with the nitrogen molecule for incident-electron energies from threshold up to 600 eV. The relative cross sections for each {ital v}{prime} family are in good agreement with the theoretical values. From the measured optical emission cross section, the apparent excitation cross sections for the {ital v}{prime}=0,1,2,3,4 vibrational levels of the {ital C}{sup 3}{Pi}{sub {ital u}} electronic states are determined. A comparison of these apparent cross sections with the relative direct excitation cross sections predicted by the Franck-Condon principle suggests that the population of the {ital C}{sup 3}{Pi}{sub {ital u}} state in an electron-beam experiment for the {ital v}{prime}=0,1, and 2 levels is primarily due to direct excitation with minor contributions from cascade. For the {ital v}{prime}=3 and 4 levels, the direct excitation cross sections are much smaller so that a larger percentage population is attributed to cascade. The relative intensities of the various ({ital v}{prime},{ital v}{double_prime}) bands in the electron-beam experiments are also compared with those observed in a dc discharge. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 279911
• Journal Information: Physical Review A, Vol. 53, Issue 4; Other Information: PBD: Apr 1996
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
NITROGEN
ELECTRON-MOLECULE COLLISIONS
ELECTRONIC STRUCTURE
EMISSION SPECTRA
EXCITATION
THRESHOLD ENERGY
ELECTRON BEAMS
EV RANGE
NITROGEN MOLECULES
BAND STRUCTURE