THE IONIZATION AND DISSOCIATION OF SOME HALOGEN MOLECULES BY ELECTRON IMPACT

1960 ◽  
Vol 38 (3) ◽  
pp. 407-420 ◽  
Author(s):  
D. C. Frost ◽  
C. A. McDowell
Keyword(s):  
Electron Impact ◽  
Excited States ◽  
Electronic Structures ◽  
Negative Ions ◽  
Molecular Ions ◽  
Negative Ion ◽  
Iodine Monochloride ◽  
Monoenergetic Electron ◽  
Iodine Monobromide ◽  
Ionization Processes

The ionization and dissociation of chlorine, bromine, iodine, iodine monochloride, and iodine monobromide by electron impact have been studied in a mass spectrometer which uses a monoenergetic electron source. Many ionization potentials have been observed for these molecules which, of course, refer to the formation of the parent molecular ions in different excited states. These experimental results are discussed in terms of simple molecular orbital theories of the electronic structures of the different halogen molecules.Electron-induced dissociative ionization processes for the different substances have also been studied. Where possible, appearance potentials of both the positive and negative ions have been determined. These results have been used to construct potential energy diagrams illustrating the origin of some of the negative ion and dissociation processes observed.

Metastable yield of argon between 23 and 37 eV by electron impact

1979 ◽  
Vol 57 (10) ◽  
pp. 1624-1633 ◽  
Author(s):  
P. Marchand ◽  
J. Cardinal
Keyword(s):  
Electron Impact ◽  
Excited States ◽  
Signal To Noise Ratio ◽  
Negative Ion ◽  
Photon Yield ◽  
Large Signal ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Yield Curves ◽  
Noise Ratio

The metastable yield of argon excited by monoenergetic electron impact has been measured between 23 and 37 eV. Thanks to a large signal-to-noise ratio, many very small structures have been detected superimposed on the metastable continuum and are attributed to Ar− negative-ion states and to highly excited states of Ar. The results are compared with broadband photon yield curves and electroionization curves.

Negative Ionen durch Elektronenstoß aus organischen Nitroverbindungen, Äthylnitrit und Äthylnitrat

1967 ◽  
Vol 22 (5) ◽  
pp. 700-704
Author(s):  
K. Jäger ◽  
A. Henglein
Keyword(s):  
Electron Impact ◽  
Negative Ions ◽  
Molecular Ions ◽  
Ion Source ◽  
Negative Ion ◽  
Electron Affinities ◽  
Low Intensity ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Product Ions

Negative ion formation by electron impact has been studied in nitromethane, nitroethane, nitrobenzene, tetranitromethane, ethylnitrite and ethylnitrate. Appearance potentials, ionization efficiency curves and kinetic energies of negative ions were measured by using a Fox ion source. The electron affinities of C2H5O and of C (NO2)3 are discussed as well as the energetics of processes which yield NO2-. The electron capture in nitrobenzene and tetranitromethane leads to molecular ions [C6H5NO2~ in high, C (NO2)4 in very low intensity] besides many fragment ions. A number of product ions from negative ion-molecule reactions has also been found.

High-resolution photon yield of xenon by monoenergetic electron impact

1987 ◽  
Vol 65 (5) ◽  
pp. 510-517
Author(s):  
René Le ◽  
Pierre Marchand
Keyword(s):  
High Resolution ◽  
Electron Impact ◽  
Excited States ◽  
Broad Band ◽  
Electron Excitation ◽  
Negative Ion ◽  
Photon Yield ◽  
Monoenergetic Electron

The broad-band (165–650 nm) photon yield of xenon by monoenergetic electron excitation has been measured in the range from 10.9 eV to above 13.436 eV (2P1/2 limit). Neutral excited states and several new negative-ion states are detected. Interpretation and classification are discussed.

Studies of the ionization of molecules by electron impact - II. Excited states of the molecular ions of methane and the methyl halides

1957 ◽  
Vol 241 (1225) ◽  
pp. 194-207 ◽  
Keyword(s):  
Excited States ◽  
Electronic Structures ◽  
Mass Spectra ◽  
Electronic States ◽  
Molecular Ions ◽  
Methyl Halides ◽  
Spin Orbital ◽  
Orbital Interactions ◽  
Electronic Excited States ◽  
First Time

The ionization of methane and the methyl halide molecules by essentially mono-energetic electrons, produced by pulse techniques, has been studied in detail in a mass spectrometer. It has been possible to detect for the first time the production of the molecular ions of these compounds in most of their excited electronic states. In the cases of the ions of methyl bromide and iodide we have been able to resolve the components of the doublets of the ground 2 E states which arise from spin-orbital interactions in these molecular ions. The several ionization potentials of each of the molecules which refer to the formation of the ions in their different electronic excited states have been measured. These new results are of interest in that they enable the molecular-orbital theories of the electronic structures of methane and the methyl halides to be assessed. They also provide support for recent theories of the origin of the ions in the mass spectra of organic compounds. It has been demonstrated that there is a monotonic relationship between the ionization potential of electrons in the [ σα 1 ] bonding orbital localized in the C— X bond of these molecules and the corresponding bond dissociation energy.

Electron impact studies. XXXII. Negative-ion mass spectra of aromatic compounds containing the =N-O- substituent

1968 ◽  
Vol 21 (8) ◽  
pp. 2031 ◽  
Author(s):  
JH Bowie ◽  
SO Lawesson ◽  
BS Larse ◽  
GE Lewis ◽  
G Schroll
Keyword(s):  
Electron Impact ◽  
Aromatic Compounds ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Negative Ion ◽  
Skeletal Rearrangement ◽  
Marked Contrast ◽  
Azoxy Compounds ◽  
Positive Ion ◽  
Fragmentation Processes

The negative-ion mass spectra of aromatic azoxy compounds, nitrones, and N-oxides exhibit pronounced molecular ions and simple fragmentation processes. No skeletal-rearrangement fragments are produced upon electron impact, in marked contrast to those exhibited in the positive-ion spectra of these compounds.

scholarly journals A novel rocket borne ion mass spectrometer with large mass range: instrument description and first flight results

2020 ◽  
Author(s):  
Joan Stude ◽  
Heinfried Aufmhoff ◽  
Hans Schlager ◽  
Markus Rapp ◽  
Frank Arnold ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Negative Ions ◽  
Mass Range ◽  
Large Mass ◽  
Molecular Ions ◽  
Negative Ion ◽  
Cluster Ions ◽  
The Arctic ◽  
Atmospheric Species ◽  
Smoke Particles

Abstract. We present a novel rocket borne ion mass spectrometer ROMARA (ROcket borne MAss spectrometer for Research in the Atmosphere) for measurements of atmospheric positive and negative ions (atomic, molecular and cluster ions) and positively and negatively charged meteor smoke particles. Our ROMARA instrument has, compared to previous rocket borne ion mass spectrometers, a markedly larger mass range of up to m/z 2000 and a larger sensitivity, particularly for meteor smoke particle detection. Mayor objectives of this first ROMARA flight included: a functional test of the ROMARA instrument, measurements between 55 km and 121 km in the mass range of atmospheric positive and negative ions, a first attempt to conduct mass spectrometric measurements in the mass range of meteor smoke particles with mass to charge ratios up to m/z 2000, and measurements inside a polar mesospheric winter echo layer as detected by ground based radar. Our ROMARA measurements took place on the Arctic island of Andøya/Norway around noon in April 2018 and represented an integral part of the PMWE rocket campaign. During the rocket flight, ROMARA was operated in a measurement mode, offering maximum sensitivity and the ability to qualitatively detect total ion signatures even beyond its mass resolving mass range. On this first ROMARA flight we were able to meet all of our objectives. We detected atmospheric species including positive atomic, molecular and cluster ions along with negative molecular ions up to about m/z 100. Above m/z 2000, ROMARA measured strong negative ion signatures, which are likely due to negatively charged meteor smoke particles.

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