2007 Fiscal Year Final Research Report Summary
Investigation of molecular multiply excited states and their quantum dynamics
| Project/Area Number |
17350006
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Tokyo Institute of Technology |
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Principal Investigator |
KOUCHI Noriyuki Tokyo Institute of Technology, Chem. Department, Professor (50161873)
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| Co-Investigator(Kenkyū-buntansha) |
KITAJIMA Masashi Tokyo Institute of Technology, Chem. Department, Associate Professor (20291065)
ODAGIRI Takeshi Tokyo Institute of Technology, Chem. Department, Assistant Professor (80282820)
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| Project Period (FY) |
2005 – 2007
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| Keywords | one-electron mean field approximation / Born-Oppenheimer approximation / multiply excited molecules / coincidence measurements / production of a photon-pair / electron collision / synchrotron radiation |
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| Research Abstract |
Revealing the multiple excitation in a molecule and subsequent decay of the multiply excited states is a challenging subject in physical chemistry since the independent electron model and the Born-Oppenheimer approximation are less available than in the electronic states below the first ionization potential We established the electron energy-loss spectroscopy tagged with photons and (γ, 2γ) spectroscopy, both of which are powerful for observing the multiply excited molecules. In the present work, we have aimed at investigating multiply excited molecules and their quantum dynamics. The molecules of interest range from diatomic molecules to polyatomic molecules.
We have measured the electron energy-loss spectra of CH_4 tagged with the Lyman-α photons at 80 eV incident electron energy and 12 and 24° electron scattering angle in the range of energy loss 20-46 eV. The peaks originating from doubly excited states have been observed as well as those originating from singly excited states. Interestingly, the former peaks are more intense than the latter ones. Angle-differential cross sections for the double excitation have been measured for the first time as a function of scattering angle, which depend on the scattering angle in a different manner from those of the single-excitation. Almost the same results were obtained for NH_3.
We have measured the cross sections for the generation of a pair of photons by a single photon absorption of an N_2 and an O_2 molecule as a function of incident photon energy in the range 23-50 eV. Peaks originating from multiply excited states have been observed. Interestingly, some of them lie in the range beyond the double ionization threshold.
We have concluded from the present work that the multiply excited states generally exist in a wide range of molecules and their quantum dynamics is not amenable to what we know about the singly excited molecules.
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Research Products
(32 results)
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[Journal Article] The electron-energy-loss spectra of methane tagged with Lyman-α photons in the range of doubly excited states2007
Author(s)
T., Nakazato, T., Odagiri, H., Fukuzawa, H., Miyagi, L., Ishikawa, M., Kitajima, N., Kouchi
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Journal Title
Journal of Physics B : Atomic, Molecular and Optical Physics 40(12)
Pages: 2459-2470
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Doubly excited states of methane produced by photon and electron interactions2005
Author(s)
H., Fukuzawa, T., Odagiri, T., Nakazato, M., Murata, H., Miyagi, N., Kouchi
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Journal Title
Journal of Physics B : Atomic, Molecular and Optical Physics 38(5)
Pages: 565-578
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Doubly excited states of NH_3 as probed by the Lyman-α fluorescence, A comparison between the electron and photon interactions2007
Author(s)
L., Ishikawa, T., Odagiri, T., Nakazato, M., Kurokawa, K., Yachi, M., Kitajima, N., Kouchi
Organizer
15th International Symposium on Electron-Molecule Collisions and Swarms
Place of Presentation
Reading, UK
Year and Date
2007-08-03
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Doubly excited states of CH_4 as studied by imaging electron-energy-loss spectra tagged with the Lyman-a photons2007
Author(s)
T., Nakazato, T., Odagiri, K., Yachi, L., Ishikawa, H., Fukuzawa, H., Miyagi, M., Kitajima, N., Kouchi
Organizer
15th International Symposium on Electron-Molecule Collisions and Swarms
Place of Presentation
Reading, UK
Year and Date
2007-08-03
Description
「研究成果報告書概要(欧文)」より
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