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 40, Issue 5
Displaying 1-3 of 3 articles from this issue
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INTEGRATED PAPER
  • Synthesis of Molecules in Dense Interstellar Clouds via Gas-Phase Chemistry
    Toyoharu UMEBAYASHI
    1992 Volume 40 Issue 5 Pages 241-269
    Published: 1992
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.40.241
    JOURNAL FREE ACCESS
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    We first describe physical and chemical properties of interstellar medium in each of six different phases: coronal gas, intercloud medium, H II region, diffuse cloud, dark cloud, and molecular cloud. Theoretical studies on the interstellar chemistry are summarized briefly. A detailed model for the gas-phase chemistry in dense insterstellar clouds is presented. We calculate the abundances of the various molecules for pseudo-time-dependent model, in which the physical conditions are assumed to be constant. Our result indicates that the gas-phase reactions can produce large abundances of complex molecules at time well before steady state is reached. We also study the gas-phase chemistry as a function of gas density and temperature.
    The preliminary results on the chemical evolution of the contracting interstellar clouds are represented. Models and rate coefficients of the gas-phase chemistry, the effects of dust grains, and the implications of our theoretical results are also discussed.
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REGULAR PAPER
  • EI Mass Spectra of the New Ring-enlargement Products in the Lead Tetraacetate Oxidation of l-2(10)-Pinene
    Yoshiharu MATSUBARA, Masanori MORITA, Mitsuru NAKAYAMA, Shin-ichi TAKE ...
    1992 Volume 40 Issue 5 Pages 271-276
    Published: 1992
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.40.271
    JOURNAL FREE ACCESS
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    From the EI mass spectra of the two new ring-enlargement products, (1R,6S)-7,7-dimethylbicyclo[4.1.1]octan-2-one and (1S,6S)-7,7-dimethylbicyclo[4.1.1]octan-3-one obtained by the lead tetraacetate oxidation of l-2(10)-pinene, we can find the distinct fragment ions at m/z 110 and m/z 111, respectively. The difference between the structures of these two ions was discussed by using B/E constant linked scan method and their exact mass spectral data. Consequently, it was considered that the ion of m/z 110 keeps the gem-dimethyl bridged structure, while the ion of m/z 111 is formed by the elimination of gem-dimethyl group.
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TECHNICAL REPORT
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