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

对熔融Cu（Cl_ <1-X> BR_X）混合物进行了超声速度，声音衰减和密度测量，以研究热力学和动态性能。该系统的绝热兼容性是从观察到的超声速度和密度获得的。观察到的可压缩性在Cu周围具有最大值（Cl_ <0.2> BR_ <0.8>），这表明熔融盐混合物的波动很大。声音衰减显示在相同成分附近的温度依赖性很大。熔融CUX（X = Cl，BR）和AGX（X = Cl，I）的EXAFS测量已在熔化温度附近进行，以研究部分结构。所获得的Cu-Halogen和Ag-Halogen距离的距离比通过同位素替代方法从中子脱附测量获得的距离短约0.1a-0.2a，结果表明簇形成（X = Cl，Br）和Agx（X = Cl，X = Cl，I）在液态状态和液态较大。沿着液体曲线和高于临界点闭合的临界点的温度下，以供液体BI-GA合金。在临界浓度下观察到了结构因子的显着变化，绝热兼容性的温度系数显示出高于不可错位差距区域的值。这表明，由于热搅拌而引起的空间波动不会影响遗漏差距区域的可补充性，并且可以轻松地重新排列原子，以使较小的空间波动的首选结构在470C和570C时通过X射线和中性扩散测量了较小的空间波动。从此差异在获得的电荷分布函数下，从该差异中评估了离子电子相关函数和价电子分布，显示在0.8a和1.7a左右熔化温度的距离处的两个峰。分别对应于休息室对电子的分布和中央校离子周围的共价电子的分布。在570°C时，在电子电荷分布中的1.1a附近的距离处观察到单个峰。这对应于局部电荷密度分布从非金属状态变为液体TE中的金属状态。较少的