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Structure and Dynamics on Metal-Nonmetal transition in Ionic Liquids

离子液体中金属-非金属转变的结构和动力学

基本信息

批准号：
04640348
负责人：
TAKEDA Shin'ichi
金额：
$ 1.15万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The ultrasonic velocity, sound attenuation and density measurements have been carried out for molten Cu(Cl_<1-x>Br_x) mixtures to investigate the thermodynamic and dynamical properties. The adiabatic compressibility of this system was obtained from the observed ultrasonic velocity and density. The observed compressibility has the maximum value around Cu(Cl_<0.2>Br_<0.8>), which suggests large fluctuaion in the molten salt mixtures. The sound attenuation shows large temperature dependence around the same composition.EXAFS measurement for molten CuX(X=Cl, Br) and agX(X=Cl, I) has been carried out near the melting temperature to study the partial structure. The obtained Cu-halogen and Ag-halogen distances are about 0.1A-0.2A shorter than the distances obtained from neutron deffraction measurement by isotopic substitution method and the results suggest the cluster formation such as a CuX(X=Cl, Br) and AgX(X=Cl, I) trimmer in the liquid state.Neutron diffraction, ultrasonic velocity and den … More sity measurements have been carried out for liquid Bi-Ga alloys along the liquidus curve and at temperatures above the critical point where the miscibility gap closes. A remarkable change in the structure factor has been observed at the critical concentration, and the temperature coefficient of the adiabatic compressibility shows rather small value above the miscibility gap region. This suggests that the spatial fluctuation due to the thermal agitation does not affect the compressibility in the miscibility gap region, and the atoms can easily be rearranged to have the preferable structure with smaller spatial fluctuations.The structure factors of liquid Te at 470C and 570C have been measured by X-ray and neutron diffraction. The ion-electron correlation function and valence electron distribution were evaluated from this difference at the two temperatures. The obtained charge distribution function shows two peaks at the distance around 0.8A and 1.7A just above the melting temperature. Those correspond to the distribution of the lone pair electrons and the covalent bonded electrons around a central tellurium ion, respectively. At 570C, single peak is observed at the distance around 1.1A in the electron charge distribution. This corresponds to the change of the local charge density distribution from non-metalllic state to metallic one in liquid Te. Less

本文对Cu（Cl_ Br_x）混合液的声速、声衰减和密度进行了测量<1-x>，以研究其热力学和动力学性质。由声速和密度的测量结果得到了该体系的绝热压缩系数。在Cu（Cl_ Br_）附近压缩系数最大<0.2><0.8>，说明熔盐混合物的压缩系数波动较大。对CuX（X=Cl，Br）和AgX（X=Cl，I）熔体在熔化温度附近进行了EXAFS测量，研究了其部分结构。用同位素替代法测得的Cu-卤素和Ag-卤素距离比中子衍射法测得的距离小0.1A-0.2A，表明在液态下形成了CuX（X=Cl，Br）和AgX（X=Cl，I）等团簇。 ...更多信息已经对液态Bi-Ga合金进行了沿着液相线测量，并且在高于临界点的温度下测量，在临界点处，可熔性间隙闭合。在临界浓度下，结构因子发生了显著变化，绝热压缩温度系数在绝热间隙区以上表现出较小的值。这表明，热扰动引起的空间涨落不影响可压缩性，原子在较小的空间涨落下很容易重新排列，得到较好的结构.用X射线和中子衍射测量了470 ℃和570 ℃下液态Te的结构因子.从这两个温度下的差异，离子-电子相关函数和价电子分布进行了评估。所得到的电荷分布函数在熔化温度以上的0.8A和1.7A附近有两个峰。这些分别对应于中心碲离子周围的孤对电子和共价键电子的分布。在570 ℃时，电子电荷分布在1.1A附近出现单峰。这对应于液态Te中局域电荷密度分布由非金属态向金属态的变化。少