Analytic models of electron impact excitation cross sections
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Engineering topics
Publications and source records attributed to Green, A. E. S..
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Examination of the consequences of electron impact on water vapor in terms of the microscopic details of excitation, dissociation, ionization, and combinations of these processes. Basic electron-impact cross-section data are assembled in many forms and are incorporated into semianalytic functions suitable for analysis with digital computers. Energy deposition in water vapor is discussed, and the energy loss function is presented, along with the 'electron volts per ion pair' and the efficiencies of energy loss in various processes. Several applications of electron and water-vapor interactions in the atmospheric sciences are considered, in particular, H2O comets, aurora and airglow, and lightning.
Semiempirical cross sections of Strickland and Green (1969) are compared with and supplemented by more recent data. The composite set is used in the energy degradation calculation of electrons with emphasis on energies below 100 ev. Good agreements are obtained with accepted values of the loss function and the average electron volts per ion pair at high energies. Efficiencies associated with various loss channels are obtained. The relationship with the recent Mariner UV data is discussed.
We determine a comprehensive set of electron impact cross sections for carbon monoxide mainly on the basis of recently accumulated data on electron impact spectra, the Born approximation at high energies, and simple rules developed earlier to take into account low-energy effects. The calculation of the complete energy degradation of electrons incident on CO is carried out with these input cross sections, and the efficiencies associated with possible loss channels are presented.
Atomic physics is so intimately entwined with planetary aeronomy that progress in this geophysical-astronomical discipline is dependent in large measure upon progress in certain phases of atomic physics. The interdependence is illustrated by a discussion of photon, electron, and proton stimulation of the dayglow and the aurora. Calculations are given for the excitation of various states in N2, O2, and O as a result of electron energy degradation, assuming a gas mixture appropriate to 120 km. Emphasis is given to the O2(a 1 Delta g) 1.27 micron emission and to the low energy region in areas where many competing mechanisms enhance or inhibit certain spectral emissions.
An analytic form is given for the energy-transfer rate from photoelectrons to thermal electrons. The expression fits the classical formulation of Itakawa and Aono (1966) at low energies and gives a smooth transition to fit the quantum mechanical equation of Schunk and Hays (1971) at higher energies. The corresponding loss function or stopping power has a form that is convenient in auroral and dayglow calculations.
Atomic nitrogen far UV emission excitation in auroral ionosphere due to electron impact dissociations
Polar cap atomic processes stimulated by photons, electrons and protons, considering particle morphology
Carbon dioxide electron impact cross sections, analyzing discrete excitation, autoionization, direct and dissociative ionization and use to aeronomy
Semiempirical electron impact cross sections and energy loss functions applied to dayglow and auroral intensities calculation, discussing atomic and aeronomic implications
Fundamental mechanisms in polar cap phenomena related to atomic physics
Three energy dependent quantities examined for gases, describing relation between ionization yields, cross section and loss functions
Energy loss functions for protons and electrons in atomic and molecular gases and various metals, noting application to planetary atmospheres studies
Semiempirical electron impact cross sections for He from oscillator strengths, using Born approximation
Electron impact cross sections used to determine helium collision cross sections sets
Electron impact excitation and ionization cross sections data of molecular nitrogen synthesized using modified Born approximation
Inelastic electron impact cross sections for ionization and vibrational excitation of atmospheric molecular oxygen
Auroral transition radiation calculated from electron impact