Local structure in ZrW2O8 from neutron total scattering
Local structure in ZrW2O8 from neutron total scattering
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中子全散射中 ZrW2O8 的局域结构
DOI：
10.1088/0953-8984/19/33/335215
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
M. Dove
中科院分区：
文献类型：
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作者：
M. Tucker;D. Keen;John S. O. Evans;M. Dove
用中子总散射数据的逆蒙特卡罗(RMC)模拟方法研究了负热膨胀材料ZrW2O8低温有序相的局域结构。用RMC导出的模型得到的键长和键角的瞬时分布描述了局域结构，同时与平均晶体结构一致。这些结果以及它们随温度的变化表明，大部分原子的均方位移是由ZrO_6八面体和WO_4四面体的刚性单位模(RUM)运动所解释的。本文提供的详细结构描述进一步支持了NTE在ZrW2O8中的基本RUM解释的主导地位，其中刚性的ZrO6和WO4多面体通过柔性的Zr-O-W键连接在一起。
The local structure of the low-temperature ordered phase of the negative thermal expansion (NTE) material ZrW2O8 has been investigated by reverse Monte Carlo (RMC) modelling of neutron total scattering data. The local structure is described using the instantaneous distributions of bond lengths and angles obtained from the RMC-derived models which are simultaneously consistent with the average crystal structure. These results, together with their variation with temperature, show that the majority of the mean squared displacements of the atoms are accounted for by rigid unit mode (RUM) motions of the ZrO6 octahedra and WO4 tetrahedra. The detailed structural description presented in this paper further supports the dominance of the basic RUM interpretation of NTE in ZrW2O8 where rigid ZrO6 and WO4 polyhedra are joined by flexible Zr–O–W linkages.