New model for electron-impact ionization cross sections of atoms and molecules
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
- Department of Physics and Astronomy, University of Nebraska--Lincoln, Lincoln, Nebraska 68588-0111 (United States)
A new theoretical model for electron-impact ionization cross sections for atoms and molecules is presented. The new model combines the binary-encounter theory and the Bethe theory for electron-impact ionization, and uses minimal theoretical data for the ground state of the target atom or molecule. Two versions of the model are presented. The first one, the Binary-Encounter-Dipole (BED) model, requires the knowledge of continuum oscillator strengths and produces the differential ionization cross section, i.e., energy distribution of ejected electrons. The differential cross section is then integrated over the ejected electron energy to obtain the total ionization cross section. The second version, the Binary-Encounter-Bethe (BEB) model, assumes a simple form of the continuum oscillator strength to obtain a compact and analytic form of the total ionization cross section. We found that both the BED and BEB models provide total ionization cross sections from threshold to several keV in incident energy within 5{percent} to 15{percent} of known experimental data for many neutral targets. The total ionization cross sections are expressed in compact analytic expressions suitable for use in modeling, e.g., of plasmas and radiation effects. We found that the BEB model is particularly effective in estimating total ionization cross sections of complex molecules. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 450150
- Report Number(s):
- CONF-960155--
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 381; ISSN APCPCS; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Binary-encounter-dipole model for electron-impact ionization
Electron-impact total ionization cross sections of CH and C{sub 2}H{sub 2}