| 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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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥12,580,000 (Direct Cost: ¥11,800,000、Indirect Cost: ¥780,000)
Fiscal Year 2007: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2006: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2005: ¥6,200,000 (Direct Cost: ¥6,200,000)
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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 / NO / NH_3 / N_2 / O_2 / 原子・分子物理 / 量子エレクトロニクス / プラズマ・核融合 / 放射線、X線、粒子線 / 量子ビーム |
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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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