Journal of the Mass Spectrometry Society of Japan
Online ISSN : 1880-4225
Print ISSN : 1340-8097
ISSN-L : 1340-8097
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Volume 22, Issue 4
Displaying 1-9 of 9 articles from this issue
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  • The Fragmentation Mechanisms in CH3X Interpreted by Using the Molecular Orbital Method
    SHIGERU IKUTA, KENJI YOSHIHARA, TAKANOBU SHIOKAWA
    1974 Volume 22 Issue 4 Pages 233-238
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.233
    JOURNAL FREE ACCESS
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    The breakdown curves of various CH3X after charge exchange reactions were obtained using a double mass spectrometer of the perpendicular type, and it was found that the C-X bond was easy to dissociate in methylhalides(Group A)whereas it was not in methylamine, methanol and methylmercaptan(Group B). The difference of the C-X bond rupture between two groups was well explained on the basis of the eigenvectors calculated by the Extended Hiickel Molecular Orbital method. It is obvious that the fragmentation directly occurs at the bond at which the electron is ejected.
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  • Application of Molecular Orbital Calculation to Fragment Ionization Processes in Ethanol and Ethylamine
    SHIGERU IKUTA, KATSUNORI HARADA, KENJI YOSHIHARA, TAKANOBU SHIOKAWA
    1974 Volume 22 Issue 4 Pages 239-244
    Published: December 31, 1974
    Released on J-STAGE: July 05, 2011
    DOIhttps://doi.org/10.5702/massspec1953.22.239
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    Applicability of the MO interpretation for the phenomena of fragment ionization processes in ethanol and ethylamine has been studied. The double maxima of the C2H4OH+ ion and of the CH2OH+ ion, which are not easily accounted for by the quasi-equilibrium theory, were well explained by our molecular orbital calculation. It was also found that appearance of fragment ions and that of the band in photoelectron spectra in these substances are correlated to each other. From these results it was confirmed that bond scission occurs at the bond at which the electron is ejected.
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  • Configurational Effects of Fragment Ionization Processes in Propanols and Butanols
    SHIGERU IKUTA, KENJI YOSHIHARA, TAKANOBU SHIOKAWA
    1974 Volume 22 Issue 4 Pages 245-249
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.245
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    Applicability of our theory for the phenomena of fragment ionization processes to large molecules and to the effect of configuration of the molecules was studied. Two kinds of propanols and four kinds of butanols were treated for the above purpose. It was clearly found that the differences of the mass spectra by different configurations of the molecules are well interpreted by our interpretation including the molecular orbital treatment. Therefore, it is clear that the mass spectra by electron impact may be also predicted by molecular orbital assignment in various occupied molecular orbitals.
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  • A Simple Method of Simultaneous Detection of Thermal Ions and Neutral Molecules Emitted from Thick Layers of Unitary Alkali Halide on a Metal Surface
    HIROYUKI KAWANO
    1974 Volume 22 Issue 4 Pages 251-268
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.251
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    A simple ion source was designed and developed to study the thermal ionic and neutral emission from thick layers of unitary alkali halide(MX)deposited on a metal surface. Besides a platinum ribbon(F1, 0.02 cm2 )functioning as the substrate metal, this ion source has a second platinum filament(F2)as a neutral beam detector and also a grid(G)between F1 and F2 in order to retard the ions emitted from F1 or F2. A part of the neutral molecules(MX1°)evaporating from F1 is ionized with F2 after passing through G. In this work with potassium fluoride, the ion source was found to be quite useful as an instrument by which the primary and secondary positive ions(M1+and M2+)emitted from F1 and F2, respectively, were separated without employing any additional separator. The collection efficiency of M1+ was so high (about 41%), and hence such a weak positive ion emission from F1 as about3×103 ions/sec 0.02 cm2 at about 350°C could be detected with a vibrating reed electrometer with a maximum sensitivity of 1×10-16 A per scale division. The detection efficiency(γ2+ )of MX1° converted into M2+ under a residual gas pressare of 2× 107 Torr was(4.1±2.0)×105, which was determined by a convenient method developed in this work. Consequently, the lower detectable limit of MX1° with another electrometer having the same sensitivity as above was usually about2×107 molecules/sec.0.02 cm2. In this way the emission rates of both M1+ and MX1° could be simultaneously measured as a function of the surface temperature(T1)and the mean sample layer thickness(θ1)on F1 over the ranges of 350-460°C and 103 -1 molecular layers, respectively. The characteristics of F2 as a neutral beam detector were examined under various conditions in order to study the probable sources responsible for the large error in γ2+. Negative ion emission from F1could be detected at T1≥500°C, where 77, was no longer kept constant. The effectiveness of the present instrument and method to investigate the mechanism of thermalion emission from thick alkali halide layers on a metal surface is discussed on the basis of the results obtained in this preliminary experiment.
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  • The Effect of Ammonia on the Ion-MoIecule Reactions of Hvdrocarbons
    YUKIO INOKOSHI, YOSHIHARU SHINOZAKI, TATSUO YAMANOTO
    1974 Volume 22 Issue 4 Pages 269-273
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.269
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    The ionmolecule reactions of hydrocarbons, such as isobutene, isobutane and neopentane, have been investigated in the absence and presence of ammonia in the ionization chamber of the mass spectrometer. In isobutene. butyl ions formed by the proton transfer reactions of C2H4+C3H3+, C3H5+and C4H8with iso-butene were decreased and ammoniun ions were produced remarkably when ammonia was added as a proton scavenger. Sec-propyl and-butyl ions formed by the fragmentation of parent ions of isobutane and neopentane, respec tively, were also decreased by addition of ammonia. The rate constant of the proton tran sfer reaction t-C4H9++NH3→C4H8+NH4+was found to be4. 0×10-9cc.molecule-1.sec-1. From these results it is found that ammonia serves as an effective proton scavenger for investigating the role of ionic species in the radiolysis and radiation polymerization reactions.
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  • EvoIution of Gas from Structural Materials of the High Temperature Helium Gas Loop
    HIROHITO TONE, KIICHIRO YOKOUCHI, OSAMU BABA
    1974 Volume 22 Issue 4 Pages 275-280
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.275
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    The high temperature helium gas loop, which is used for irradiation tests of the nuclear fuels of the gas cooled reactors, is constructed in JAERI(Japan Atomic Energy Research Institute). Since the maximum temperature of the helium gas coolant in the gas loop is1000°, it is necessary that the concentration of impurities present in the helium gas coolant is held less than10ppm to prevent the corrosion of structural materials. To obtain the design data of the helium coolant purification system, the outgassing behavior of the structural materials such as graphite and ceramic thermal insulator was measured by mass spectrometer and gas chromatograph. It is found by this study that the outgassing rate from graphite and ceramic thermal insulator can be expressed by the following equation, s(t)=Ge-ktt2.
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  • Determination of Stanols in Sediments by Modified GC-MS Fragmentography
    KAZUKO OGURA, TAKAHISA HANYA
    1974 Volume 22 Issue 4 Pages 281-286
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.281
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  • K+Ion Formation in Collision of Na+Ions with KCl Vapors
    HOKOTOMO INOUYE, TOSHIAKI SASAKI
    1974 Volume 22 Issue 4 Pages 287-290
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.287
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  • An Empirical Relation of Repulsive Potentials between Closed-Shell Particles to Their Atomic Properties
    HOKOTOMO INOUYE
    1974 Volume 22 Issue 4 Pages 291-295
    Published: December 31, 1974
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5702/massspec1953.22.291
    JOURNAL FREE ACCESS
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