Measurement of Appearance Potentials of Ions Produced by Electron Impact, using a Mass Spectrometer

Energetics of the Ionization and Fragmentation of Phosphorus Trifluoride by Electron Impact

“…Apart from background peaks due t o air and water there were also small peaks of variable intensity observed at m/e 20,35,36,37,38,81,85, and 104 which could be assigned to H F f , 20; Clf, 35, 37; HC~', 36, 38; SiF,', 85; and SiF,', 104. The source of HF and SiF, was thought to be from the reaction of PF, with background water, and the glass reservoir and inlet line respectively, while HCl was formed by the action of moisture on the SbF,, PCl, mixture used to prepare PF,.…”

“…of PF,' was determined from the experimental data by three procedures, namely, the "extrapolated voltage difference" (e.v.d.) method (36), the "semilogarithmic plot" (s.1.p.) method (37) Ionization by electron impact is a vertical ionization process and the probability of ionization to the ground vibrational state of the molecular ion will depend upon the relative shapes and positions of the potential energy surfaces of the neutral molecule and ground electronic state of the molecular ion.…”

Determination of bond energies by mass spectrometry. Some transition metal carbonyls

“…The procedure developed in this research to determine appearance ) potentials is an adaptation of the method of extrapolated voltage differences first proposed by Warren [25] in 1950. The method was designed to give appearance potential differences and was described by…”

Ionization Potentials of Some Perfluoroalkyl Arsines

“…The ionization potentials were obtained by electron impact nlass spectrometry, and were derived by treating the relevant ionization efficiency curve and a standard (Se+ or Iir+) with the Warren extrapolation method (2). The results, although reproducible to 0.1 ev, may well be slightly greater than the adiabatic values; however, this is not expected to LIII~LIIY influence the trends shown within the groups of similar nlolecular species dealt with here.…”