Dynamics of Moiecular Glasses Studied by Using Partially Deuterated Systems

使用部分氘化系统研究分子玻璃动力学

基本信息

批准号：
10640369
负责人：
YAMAMURO Osamu
金额：
$ 2.11万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640369/
关键词：
Neutron Scattering Glass Boson Peak Alcohol Hydrogen Bond Dynamic Structure Factor Deuteration 重水素置換

项目摘要

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.

我们已经测量了一些氘化醇的玻璃杯的非弹性中子散射（INS），以研究玻色子峰的显微镜机理。测得的样品是在羟基和/或烷基上有选择地脱离玻璃丙醇和甘油。观察到的INS光谱由氢原子的部分的振动支配，因为氢原子的不连贯散射横截面比其他原子大的10倍以上。我们使用了属于东京大学固态物理研究所的AGNES光谱仪。在丙醇中，玻色峰出现在大约2 MeV和3.5 MeV中。两种醇的氘化都不会改变峰值能量和强度。这表明玻色子峰的起源是氢键网络（或链）和酒精零件的合作振动。目前的结果与Nakayama最近开发的破碎网络模型一致。我们还进行了INS实验的墨水疗程[KPOI D23E D2 d2 ・0.70D22E D2O）的INS实验。通过在英国卢瑟福·阿普尔顿实验室使用玛丽光谱仪。连贯的INS频谱显示，在不一致的光谱中观察到在3-4 MeV处观察到的玻色子分为2.5和6 MeV的两个峰。这是一个可能与本材料的一维网络有关的新发现。我们还发现了动量与能量传递平面中散射强度图中声音子的分散性质。色散的周期性对应于静态结构因子S（q）的周期性。这种现象可能与定义明确的网络玻璃局部结构有关。