Electron energy loss spectra of the discharge afterglows of N2, H2
Electron energy loss spectra of the discharge afterglows of N2, H2
An electrons energy loss spectrometer has been designed and constructed to study differential collision cross-section phenomona of the transient species produced by a microwave discharge in atmospheric gases. The spectrometer incorporated twin hemispherical electrostatic velocity analyzers and a crossed electron-target beam configuration. The design of the electron optical transport system united the production of a monochromatic incident electron beam with energies in the range 50 to 500 eV, with detection of energy losses of 0 to 30 eV in the scattered beam. The overall energy resolution of the instrument was better than 40 meV. To facilitate a study of the angular dependence of differential cross-sections, electron scattering in the range -5: to +250 could be detected, the angular resolution being better than 10. High resolution electron energy loss spectra in the energy loss range 7.0 to 18.5 eV, observed downstream of a Nitrogen discharge, have revealed the first nine vibrationally excitedground electronic states of N2 to be substantially populated. The population distribution, however, was found to be non-Boltzmann like the populations of the first six vibrational levels (v"=0 to 5), being 60%, 18%, 8.5%, 4.25%, 3.25% and2.75% respectively. Also observed in the Nitrogen Afterglow energy loss spectrum were the atomic transitions: NI, 2s22p23s 4p F 2s22p3 4S and 2s2p4 4P F 2s22p3 4S.Atoms and vibrationally excited ground state molecules were also detected in the afterglow of Hydrogen, but not in a similar study of Carbon Monoxide.
University of Southampton
1976
White, Melvin Donald
(1976)
Electron energy loss spectra of the discharge afterglows of N2, H2.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
An electrons energy loss spectrometer has been designed and constructed to study differential collision cross-section phenomona of the transient species produced by a microwave discharge in atmospheric gases. The spectrometer incorporated twin hemispherical electrostatic velocity analyzers and a crossed electron-target beam configuration. The design of the electron optical transport system united the production of a monochromatic incident electron beam with energies in the range 50 to 500 eV, with detection of energy losses of 0 to 30 eV in the scattered beam. The overall energy resolution of the instrument was better than 40 meV. To facilitate a study of the angular dependence of differential cross-sections, electron scattering in the range -5: to +250 could be detected, the angular resolution being better than 10. High resolution electron energy loss spectra in the energy loss range 7.0 to 18.5 eV, observed downstream of a Nitrogen discharge, have revealed the first nine vibrationally excitedground electronic states of N2 to be substantially populated. The population distribution, however, was found to be non-Boltzmann like the populations of the first six vibrational levels (v"=0 to 5), being 60%, 18%, 8.5%, 4.25%, 3.25% and2.75% respectively. Also observed in the Nitrogen Afterglow energy loss spectrum were the atomic transitions: NI, 2s22p23s 4p F 2s22p3 4S and 2s2p4 4P F 2s22p3 4S.Atoms and vibrationally excited ground state molecules were also detected in the afterglow of Hydrogen, but not in a similar study of Carbon Monoxide.
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Published date: 1976
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Local EPrints ID: 467196
URI: http://eprints.soton.ac.uk/id/eprint/467196
PURE UUID: fb121bd4-f0dd-487b-b51c-68c70b8e413c
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Date deposited: 05 Jul 2022 08:16
Last modified: 05 Jul 2022 08:16
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Author:
Melvin Donald White
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