Development of Wideband Terahertz Emission Spectroscopy by using heterodyne receiver
| Project/Area Number |
17550020
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Toho University |
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Principal Investigator |
OZEKI Hiroyuki Faculty of Science, Associate Professor, 理学部, 助教授 (70260031)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | emission spectroscopy / absolute intensity measurement / terahertz frequency region / pressure coefficient / hydrogen chloride / acetonitrile / 受動分光法 / 圧力パラメーター / テラヘルツ / 発光分光 |
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| Research Abstract |
The purpose of this study is to develop gas-phase emission spectroscopy at terahertz region by using heterodyne detection technique. The method has a capability of taking a wideband frequency spectra (1000-4000 MHz) without degrading frequency accuracy obtained in the conventional absorption spectroscopy (100 kHz or less). We demonstrated the following three points in order to demonstrate these advantages; 1. Spectroscopic measurements of pressure-broadened spectra to discuss its shape and derive pressure broadening or shift parameters. 2. Easy assignments of transitions of the molecule showing a complicated spectral pattern, and 3. Multiple or simultaneous quantum states observation. The experimental setup used in the present study is a superconducting receiver system at JAXA in Tsukuba Space Center operated at 0.6 THz
First, we have succeeded to measure emission spectra of J=1-0 rotational transition of the two isotopomers of the hydrogen chloride molecule in the pressure range betwee
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n 0.3 to 200 hPa. Pressure broadening and pressure shift parameters against nitrogen and oxygen for the molecule can be derived by analyzing the shape of the observed emission spectra. The same kind of measurements was also conducted for the acetonitrile molecule, which is considered to be important in the tropospheric chemistry. Reliable pressure broadening and shift parameters will contribute to retrieve abundance of the molecule from the observed atmospheric spectra by remote sensing technique
We have also tried to detect emission spectra from the plasma obtained by discharging a mixture of the acetonitrile molecule and helium. The hydrogen cyanide, one of the reaction products produced by a discharge, is observed with its vibrational excited state. Our method makes it possible to estimate of the vibrtional temperature of the molecule to be approximately 410 K. This kind of information will contribute to kinetic study of the molecules.
These results will be published in the Journal of Molecular Spectroscopy. Less
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Report
(3 results)
Research Products
(1 results)
