用六维团簇模型和定量会聚束电子衍射优化i-AlPdMn准晶的结构因子

基于二十面体AlPdMn准晶的六维团簇模型，用定量会聚束电子衍射法优化了二十面体AlPdMn准晶的8个独立的强反射结构因子。将优化得到的结构因子替换X射线衍射实验得到的结构因子，并与其它的X射线衍射实验得到的结构因子相结合，用Fourier合成的方法得到二十面体AlPdMn准晶的电荷密度分布和差值电荷密度分布。所得差值电荷密度表明，当Al原子的最近邻原子为Mn时，Al原子失去较多的电子，Mn原子得到电子，说明发生了Al的外层电子向Mn原子转移，Mn显示负的化合价。这一结果与他人的理论计算结果相符。

Refinements of structure factors of i-AlPdMn quasicrystal by using six-dimensional cluster model and quantitative convergent beam electron diffraction

Based on the six-dimensional cluster model of i-AlPdMn phase,eight independent structure factors of strong reflections of i-AlPdMn were refined with quantitative convergent beam electron diffraction(QCBED) technique.With these structure factors obtained by using QCBED and other structure factors obtained from X-ray diffraction experiment,the charge density and difference charge density of i-AlPdMn were obtained by means of Fourier synthesis method.The difference charge density map shows that Al atoms loose significant amount of electrons when their nearest neighbour atom is Mn,and the Mn atom gains electrons.This means that the transfer of electrons from Al to Mn occurs,and Mn has a negative valence.This result agrees with the theoretical calculations of other investigators.