Absolute partial cross sections for electron-impact ionization of CH4 from threshold to 1000 eV
1997; American Institute of Physics; Volume: 106; Issue: 11 Linguagem: Inglês
10.1063/1.473468
ISSN1520-9032
AutoresH. C. Straub, Dong Lin, B. G. Lindsay, K. A. Smith, R. F. Stebbings,
Tópico(s)Analytical chemistry methods development
ResumoAbsolute partial cross sections for the production of CH4+, CH3+, CH2+ , CH+, C+, H2+, and H+ from electron-impact ionization of CH4 are reported for electron energies from threshold to 1000 eV. The product ions are mass analyzed using a time-of-flight mass spectrometer and detected with a position-sensitive detector whose output demonstrates that all product ions are completely collected. The overall uncertainty in the absolute cross section values is ±3.5% for singly charged parent ions and is slightly greater for fragment ions. Although previous measurements are generally found to agree well with the present results for CH4+ and CH3+, almost all previous work for the remaining fragment ions lies lower than the present results and in the case of H+ is lower by approximately a factor of 4.
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