| Project/Area Number |
10640369
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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 |
物性一般(含基礎論)
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| Research Institution | Osaka University |
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Principal Investigator |
YAMAMURO Osamu Graduate School of Science, Osaka University Assistant Professor, 大学院・理学研究科, 講師 (20200777)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Neutron Scattering / Glass / Boson Peak / Alcohol / Hydrogen Bond / Dynamic Structure Factor / Deuteration / 重水素置換 |
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| Research Abstract |
We have measured the inelastic neutron scattering (INS) of the glasses of some deuterated alcohols to investigate the microscopic mechanism of the boson peak. The measured samples are glassy propanols and glycerols selectively deuterated at hydroxyl and/or alkyl groups. The observed INS spectra are dominated by the vibrations of the parts with hydrogen atoms since incoherent scattering cross section of hydrogen atom is more than 10 times larger than those of other atoms. We used AGNES spectrometer belonging to Institute of Solid State Physics, the University of Tokyo. A boson peak appeared at around 2 meV in propanols and 3.5 meV in glycerols. The peak energy and intensity were not changed much by the deuterations for both alcohols. This indicates that the origin of the boson peak is the cooperative vibration of the hydrogen bond network (or chain) and alkyl parts. The present results qualitatively agreed with the broken network model recently developed by Nakayama.
We have also performed the INS experiment of the glasses of potassium metaphospate deuterate (KPOィイD23ィエD2・0.70DィイD22ィエD2O). by using MARI spectrometer in Rutherford Appleton Laboratory, UK. The coherent INS spectrum showed that the boson observed at 3-4 meV in the incoherent spectrum is split into two peaks at 2.5 and 6 meV. This is a new finding probably related to the one dimensional network of the present material. We have also found the dispersive nature of the acoustic phonon in the scattering intensity map in the momentum vs energy transfer plane. The periodicity of the dispersion corresponded to that of static structure factor S (Q). This phenomenon may be related to the well-defined local structure of the network glass.
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