Analysis of diffuse scattering from the mineral mullite
Analysis of diffuse scattering from the mineral mullite
复制标题
莫来石矿物的漫散射分析
DOI：
10.1107/s0021889894002220
复制
发表时间：
1994
影响因子：
6.1
通讯作者：
T. Welberry
中科院分区：
文献类型：
--
作者：
B. Butler;T. Welberry
本文收集了莫来石单晶Al2(Al2 + 2xSi2−2x)O10−x, x = 0.4的全往复空间漫射散射数据。利用最小二乘技术对这些数据进行了分析，通过编写一个漫射散射方程，该方程只涉及材料中特定氧位点空位之间的局部顺序。在氧空位近程强度系数中考虑了大但可预测的阳离子位移对扩散强度的影响。分析表明，空位在邻近的½< 110 >,[110],< 001 >和< 011 >原子间向量上呈负相关，而在< 010 >,< 101 >,< 1 / 2 < 112 >和< 1 / 2 < 310 >原子间向量上呈正相关。随后基于这些局部阶参数的结构蒙特卡罗模型表明，莫来石的结构是由有效的邻近空位-空位排斥相互作用主导的。提出了一个与实测的局部参数近似一致的莫来石实空间模型。
A full reciprocal-space volume of diffuse scattering data from a single-crystal of the mineral mullite, Al2(Al2 + 2xSi2 − 2x)O10 − x, x = 0.4, was collected. These data were analysed using least-squares techniques by writing an equation for the diffuse scattering that involves only the local order between vacancies on specific oxygen sites in the material. The effect of the large, but predictable, cation shifts on the diffuse intensity is taken account of in the coefficients of the oxygen-vacancy short-range-order intensities. This analysis shows that the vacancies are negatively correlated at the near-neighbour ½ 〈110〉, [110], 〈001〉 and 〈011〉 interatomic vectors and positively correlated along the 〈010〉, 〈101〉, ½ 〈112〉 and ½ 〈310〉 vectors. Subsequent Monte Carlo modelling of the structure based on these local-order parameters demonstrates that the structure of mullite is dominated by effective near-neighbour vacancy–vacancy repulsive interactions. A real-space model of mullite is presented that is approximately consistent with the measured local-order parameters.