Electron impact ionization of the SF{sub 5} and SF{sub 3} free radicals
- Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, New Jersey 07030 (United States)
- Institut fuer Physik, Ernst-Moritz-Arndt Universitaet, D-17847-Greifswald (Germany)
- Chemistry and Physics Department, William Paterson University of New Jersey, Wayne, New Jersey 07470 (United States)
We measured absolute cross sections for the electron-impact ionization and dissociative ionization of the SF{sub 5} and SF{sub 3} free radicals from threshold to 200 eV using the fast-neutral-beam technique. The total single ionization cross sections at 70 eV were found to be 5.1{times}10{sup {minus}16}thinspcm{sup 2} (SF{sub 5}) and 3.2{times}10{sup {minus}16}thinspcm{sup 2} (SF{sub 3}). The cross sections reach their maximum at about 100 eV for both radicals, with values of 5.4{times}10{sup {minus}16}thinspcm{sup 2} (SF{sub 5}) and 3.5{times}10{sup {minus}16}thinspcm{sup 2} (SF{sub 3}). Dissociative ionization is important only for SF{sub 5}, where the SF{sub 5}{sup +} parent ionization cross section and the SF{sub 4}{sup +} fragment ionization cross sections have roughly the same value. By contrast, the ionization of SF{sub 3} is dominated by the formation of SF{sub 3}{sup +} parent ions. A comparison of the measured total single ionization cross sections with calculated cross sections, using a modified additivity rule, shows excellent agreement for both radicals in terms of the absolute cross section values and the cross section shapes. Total single ionization cross sections were also calculated for SF{sub 4}, SF{sub 2}, and SF. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 662179
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 16 Vol. 109; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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