Au和Fe二十面体的高分辨透射电子显微像模拟与应变分析

像差校正在透射电子显微镜中的实现不仅提高了高分辨透射电镜的分辨率,也使人们得以直接测量材料中的原子构型。二十面体是金属与合金催化剂颗粒所具有的一种典型的结构形式,可看作由二十个四面体组成多重孪晶结构。它们在任何一个方向的投影都是两个或更多四面体的叠加,这使得它们的高分辨图像的解释变得困难。本研究构建了9种不同条件下的二十面体小颗粒模型,利用多片层法模拟颗粒的高分辨透射电子显微图像。通过对比高分辨电镜模拟像的定量分析结果与相应的结构模型,结果表明要获得精确的定量分析结果,有必要选择合适的分析区域。在特定区域,晶面间距的测量误差约2%～4%;而在其它区域,误差可达8%～10%。

HRTEM simulation and quantitative analysis of Au and Fe icosahedral nanoparticals

As a quite popular structure for metallic catalysts,the icosahedron can be regarded as a multi-twinned particle based on the face-center-cubic lattice.For this kind of structures,there is overlapping of more than two tetrahedras in any direction,making the high resolution transmission electron microscopy(HRTEM) images more difficult to explain.The problem becomes more serious when the atomic structure of the particles is to be analyzed quantitatively.In this paper we constructed several kinds of icosahedral...