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Detection of New Interstellar Molecules by Fourier Transform Millimeter-wave Spectroscopy

Research Project

Project/Area Number05453020
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Physical chemistry
Research InstitutionThe University of Tokyo

Principal Investigator

YAMAMOTO Satoshi  Graduate School of Science, University of Tokyo Associate Professor, 大学院・理学系研究所, 助教授 (80182624)

Project Period (FY) 1993 – 1994
Project Status Completed(Fiscal Year 1994)
Budget Amount *help
¥7,500,000 (Direct Cost : ¥7,500,000)
Fiscal Year 1994 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1993 : ¥5,900,000 (Direct Cost : ¥5,900,000)
KeywordsMicrowave Spectra / Millimeter-wave / Interstellar Molecules / Rorational Spectra / Free Radical / マイクロ波
Research Abstract

A Fourier transform microwave spectrometer which can be used in the millimeter-wave region is developed in order to destect rotational spectral lines of various free radicals and molecular ions with astronomical interest. An output of a frequency doubler driven by a microwave synthesizer to an output of a frequency stabilized Gunn oscillator is used as a millimeter-wave source.A main difficulty in the millimeter-wave region is found to be how to couple the millimeter-wave radiation with a Fabry-Perot cavity. Various coupling loops and coupling holes are tried in order to obtain good performance in a wide frequency region. Dimensions of the coupling hole is found to be essential to realize a sensitive spectrometer.
A discharge nozzle system is constructed to observe spectral lines of free radicals and molecular ions. By use of this, the intense spectral lines of C_3S and cyclic C_3H_2 are observed. Furthermore, the spectral lines of some free radicals such as cyclic C_3H,CCS,SO,and HC_3S are also observed with a good S/N ratio. In order to cancel the Earth's magnetic field, three Helmholtz coils are employed.
Along with the above efforts, rotational spectra of interstellar molecules (c-C_<>H_<>Si, linear C_3H,and linear C_2H) are investigated in detail by using a conventional source modulation spectrometer. Furthermore the H_2CN radical is detected as an interstellar molecule through astronomical observations with the NRAO 12 m telescope.

Report

(3results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report

Research Products

(16results)

All Other

All Publications

  • [Publications] Satoshi Yamamoto: "The Microwave Spectrum of SO in the b^1Σ^+ Electronic State" Chemical Physics Letters. 212. 113-117 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto: "Microwave Spectrum and Molecular Structure of the Cyclic C_3H Radical" Journal of Chemical Physics. 101. 5484-5493 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto: "Microwave Spectrum of the HNCN Radical in the 〓^2A″ Ground Electronic State" Journal of Chemical Physics. 101. 10350-10353 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Masatoshi Ohishi: "Detection of a New Interstellar Molecule,H_2CN" Astrophysical Journal. 427. 151-154 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Mitsuaki Izuha: "Microwave Spectrum and Molecular Structure of Silacyclopropenylidene c-C_2H_2Si" Canadian Journal of Physics. (in press).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto: "Microwave Spectrum and Molecular Structure of the HS_2 Radical" Canadian Journal of Physics. (in press).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto: ""The Microwave Spectrum of SO in the b^1SIGMA^+ Electronic State"" Chem. Phys. Lett. 212. 113-117 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto and Shuji Saito: ""Microwave Spetrum and Molecular Structure of the Cyclic C_3H Radical"" J.Chem. Phys.101. 5484-5493 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto and Shuji Saito: ""Microwave Spectrum of the HNCN Radical in the X^2A" Ground Electronic State"" J.Chem.Phys. 101. 10350-10353 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Masatoshi Ohishi, Douglas McGonagle, William M.Irvine, Satoshi Yamamoto, and Shuji Saito: ""Detection of a New Interstellar Molecule, H_2CN"" Astrophys.J.427. L51-L54 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Mitsuaki Izuha, Satoshi Yamamoto, and Shuji Saito: ""Microwave Spectrum and Molecular Structure of Silacyclopropenylidene c-C_2H_2Si"" Can, j, Phys.(in press.).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto and Shuji Saito: ""Microwave Spectrum and Molecular Structure of the HS_2 Radical"" Can. j. Phys.(in press.).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Satoshi Yamamoto: "Microwave spectrum of the HNCN radical in the X^2A" ground electronic state" Journal of Chemical Physics. 101. 10350-10353 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] Satoshi Yamamoto: "Microwave spectrum and molecular structure of the cyclic C_3H radical" Journal of Chemical Physics. 101. 5484-5493 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] Satoshi Yamamoto: "Microwave spectrum and molecular structure of the HS_2 raducak" Canadian Journal of Physics. (in press).

    • Related Report
      1994 Annual Research Report
  • [Publications] Satoshi Yamamoto: "The microwave spectrum of SO in the b^1Σ^+ electronic state" Chem.Phys.Lett.212. 113-117 (1993)

    • Related Report
      1993 Annual Research Report

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Published : 1993-04-01   Modified : 2016-04-21  

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