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

1975 ◽  
Vol 53 (6) ◽  
pp. 933-938 ◽  
Author(s):  
David F. Torgerson ◽  
John B. Westmore
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Ionization Efficiency ◽  
Negative Ion ◽  
Efficiency Curve ◽  
Group V ◽  
Fragmentation Pathways ◽  
Ion Fragmentation ◽  
Positive Ions ◽  
Significant Intensity

Relative intensities and appearance potentials of several positive ions in the mass spectrum of PF3 are reported as well as an ionization efficiency curve for F−, the only negative ion of significant intensity. Probable ion fragmentation pathways are proposed, together with heats of formation of some positive ions, and ionization potentials for PF3, PF2·, and PF. The results are compared with available data for other Group V halides.

Studies of the ionization of molecules by electron impact I. Excited states of the nitrogen molecular ion

1955 ◽  
Vol 232 (1189) ◽  
pp. 227-235 ◽  
Keyword(s):  
Electron Impact ◽  
Molecular Orbital ◽  
Excited States ◽  
Spectroscopic Data ◽  
Molecular Nitrogen ◽  
Nitrogen Molecule ◽  
Ionization Efficiency ◽  
Efficiency Curve ◽  
Pulse Technique ◽  
Good Agreement

A recently developed pulse technique which produces a beam of electrons with an energy spread of only 0·1 eV has been used to determine the ionization efficiency curve for molecular nitrogen in a mass spectrometer. Ionization to all four known excited states of the N + 2 ion, including the recently identified 2 π< u state, are clearly recognizable on the ionization efficiency curve. The several ionization potentials of the nitrogen molecule, as given by this new electron impact method, are in good agreement with the values deduced from spectroscopic data. The results are also shown to be in agreement with the expectations of the molecular orbital formula for nitrogen given some years ago by Mulliken (1932).

scholarly journals Numerical Simulations and the Design of Magnetic Field-Enhanced Electron Impact Ion Source with Hollow Cylinder Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Guochen Qi ◽  
Di Tian ◽  
Guolun Gao ◽  
Guangda Liu ◽  
Chunling Qiu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Impact ◽  
Hollow Cylinder ◽  
Impact Ionization ◽  
Transmission Efficiency ◽  
Ion Source ◽  
Ionization Efficiency ◽  
Negative Ion ◽  
Ionization Source ◽  
Electron Intensity

An electron impact ion source-adopted magnetic field-enhanced technology has been designed for enhancing the electron intensity and the ionization efficiency. Based on the ion optic focus mechanism, an electron impact ionization source was designed, and the electron entrance into the ionization chamber was designed with a hollow cylinder structure to improve the ion extraction efficiency. Numerical simulation and optimal geometry were optimized by SIMION 8.0 to provide higher electron intensity and ion transmission efficiency. To improve the electron intensity, the influence of the filament potential and magnetic intensity was investigated, and the values of 70 eV and 150 Gs were chosen in our apparatus. Based on the optimal parameters, the air in the lab and oxygen gas was detected by the homemade apparatus, and the ion intensity was detected in the positive and negative ion modes, respectively. The homemade electron impact ion source apparatus has the potential to enhance ionization efficiency applied in the mass spectrometer ionization source.

Negative-ion fragmentation pathways in 2,4,6-trinitrotoluene

1993 ◽  
Vol 28 (7) ◽  
pp. 773-779 ◽  
Author(s):  
M. L. Langford ◽  
J. F. J. Todd
Keyword(s):  
Negative Ion ◽  
Fragmentation Pathways ◽  
Ion Fragmentation

THE PHOTOIONIZATION OF NITROGEN DIOXIDE

1962 ◽  
Vol 40 (6) ◽  
pp. 1064-1067 ◽  
Author(s):  
D. C. Frost ◽  
D. Mak ◽  
C. A. McDowell
Keyword(s):  
Nitrogen Dioxide ◽  
Ionization Potential ◽  
Electron Impact ◽  
Impact Ionization ◽  
Threshold Energy ◽  
Ionization Efficiency ◽  
Efficiency Curve ◽  
Mass Spectrometric Technique ◽  
Measuring Techniques ◽  
First Ionization Potential

The ionization of nitrogen dioxide by photons has been studied using a photoionization mass spectrometric technique and also by the ordinary electron impact method. The photoionization results show a large variation in the relative ionization efficiency within the energy range 9–14 ev, and help to explain the differences between previously reported values for the first ionization potential of this compound. The photoionization efficiency curve indicates the first ionization potential to lie at 9.8 ev and inner ionization potentials to lie at about 11.1 and 12.7 ev.The electron impact ionization efficiency curve for the NO2+ ion exhibits a low ion intensity near the threshold. This confirms the viewpoint that previous determinations of the first ionization potential have employed threshold energy measuring techniques not properly suited for the type of molecule such as nitrogen dioxide which radically changes symmetry on ionization.

Electroionization of D2O and H2O and study of fragments H+ and OH+

1978 ◽  
Vol 56 (12) ◽  
pp. 1549-1558 ◽  
Author(s):  
D. Lefaivre ◽  
P. Marmet
Keyword(s):  
Electron Impact ◽  
Ion Pair ◽  
Pair Formation ◽  
Ionization Efficiency ◽  
Efficiency Curve ◽  
Ion Pair Formation ◽  
New Information

In the electroionization efficiency curve of H2O and D2O, clearly resolved newly observed structures converging to the (1b2) and (2a1) limits are reported and interpreted between threshold and 31 eV. A perturbation from the OH+ + H + 2e dissociation continuum is observed in the ionization efficiency curve of H2O. Appearance curves of H+ from H2O are analysed and the presence of ion pair formation H+ + OH− at threshold is demonstrated. Observation of these structures reveals new information on the mechanism of electron impact on molecules.

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