1991 Fiscal Year Final Research Report Summary
High-Sensitivity Submillimeter-Wave Spectroscopy of Silicon-Containing Interstellar Molecules
| Project/Area Number |
02452013
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Astronomy
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| Research Institution | Okazaki National Institutes (1991)
Nagoya University (1990) |
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Principal Investigator |
SAITO Shuji Okazaki National Institutes, Institute for Molecular Science, Department of Molecular Structure, Professor, 分子科学研究所・分子構造研究系, 教授 (30106158)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Satoshi Nagoya University, Department of Astrophysics, Research Associate, 理学部, 助手 (80182624)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Microwave spectroscopy / Submillimeter-wave spectroscopy / Multiplier / Interstellar molecule / Radio telescope / Transient molecule / Free radical / Univdentified line |
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| Research Abstract |
The effective sensitivity of the microwave spectrometer was significantly improved by introducing a quadrupler for the 400 to 500 GHz region. A detailed study on the characteristics of the multiplier revealed that the quadrupler gives significant 5th component output power in the edge frequency regions specified. This enables us to carry out moderate-sensitivity spectroscopy in the frequency region between 500 and 650 GHz. We have studied several transient molecules, especially potential candidates for interstellar molecules by using the highsensitivity submillimeter-wave spectrometer combined with the multiplier.
1. Detection of new interstellar molecules : We assigned several unidentified lines, which were dbtected toward TMC-1 and IRC+10216 by Naobeyama 45 m telescope, to two new cumulene and carbone molecules, CH_2CCC and CH_2CC. The other two free radicals, SiN and HCCN, whose spectral lines we detected first in the laboratory, were also identified as new interstellar molecules by observations using IRAM and NRAO telescopes.
2. Spectroscopy of silicon-containing molecules : Three new silicon-containing transient species, C_2H_2Si, CH_2Si, and HSiO, were detected for the first time in the discharged plasma of a mixture of SiH_4, C_2H_2, and CO with laboratory submillimeter-wave spectroscopy. Their spectral lines were analyzed to give precise molecular constants, from which fundamental information for detailed molecular structures were derived.
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