Digitale Medien
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
114 (2001), S. 1170-1177
ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
We measured absolute partial cross sections for the formation of various singly charged and doubly charged positive ions produced by electron impact on SiF4 from threshold to 900 eV using a time-of-flight mass spectrometer. Dissociative ionization was found to be the dominant process, although we found evidence of the presence of the SiF4+ parent ion in our experiment. The SiF3+ fragment ion has the largest partial ionization cross section with a maximum value of 4.3×10−16 cm2 at 90 eV. All other singly charged fragment ion cross sections are about one order of magnitude smaller at this impact energy. The cross-section values of the doubly charged ions with the exception of SiF2++ are about two orders of magnitude smaller. A comparison is made with available previously measured data. Additional measurements using a sector-field mass spectrometer revealed that all fragment ions are formed with excess kinetic energy. The experimentally determined total single ionization cross section of SiF4 is compared with results of semiempirical and semiclassical calculations and reasonable agreement is found. © 2001 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.1333018
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