| Project/Area Number |
02452083
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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 |
物理計測・光学
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| Research Institution | University of Tokyo |
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Principal Investigator |
SHIMIZU Tadao Univ. Tokyo, Fac. Science, professor, 理学部, 教授 (90011668)
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| Co-Investigator(Kenkyū-buntansha) |
KUZE Hiroaki Shizuoka Univ., Fac. Liberal Arts, assistant professor, 教養部, 助教授 (00169997)
TACHIKAWA Maki Univ. Tokyo, Fac. Sci., research assistant, 理学部, 助手 (60201612)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1991: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1990: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Keywords | evanescent wave spectroscopy / molecule scattering by the solid / supersonic molecular beam / double resonance spectroscopy / laser Stark spectroscopy / ammonia molecule / dipole transition |
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| Research Abstract |
We have carried out molecular beam spectroscopy and evanescent wave spectroscopy to study interactions between solid surface and molecules in the gas phase.
Combination of the supersonic molecular beam technique and the infrared double resonance spectroscopy enables measurements of the probability of collision induced transitions between specific vibration-rotation states of molecules. First, the molecular beam double resonance method was tested In the measurement of the state-to-state cross section of the rotational transitions in NH_3 caused by the dipole-quadrupole interaction with nonpolar target molecules. Our experimental procedure has been justified because the obtained cross sections agree quite well with those nonempirically calculated from a collision theory.
Then, we applied the method to observe collision-induced population change in the rotational states of NH_3 scattered from solid surfaces, such as glass, Al, and Au. It has been found that the selection rule in the dipole transition dominates the collision induced transition on glass surface. On the other hand, the molecule makes a hard collision with metal surfaces, and there is no definite selection rule.
Simultaneously, we have developed a evanescent-wave laser spectrometer, and detected rotation-vibration spectra of NH_3 molecules close to NaCl surface. The spectral line of NH_3 near the surface was broadened approximately by 50 %, compared with that in the gas phase. The line width was proportional to the square root of the surface temperature. This may be attributed to the phase relaxation induced by the interaction with the solid surface.
In the future, we are going to combine the molecular beam method with the evanescent wave spectroscopy for further research of the scattering process on solid surface.
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