Accurate structure analyses of fullerene compounds by the Maximum Entropy Method

这个研究有三个目标。它们是1）要建立富勒尼化合物的精确结构分析方法， 2）要在电子水平找到内氢金属富勒尼化合物的精确结构，3）要更好地理解富勒尼化合物及其结构特性之间的超导电性。首先，我们找到了Rietveld精炼剂和最大熵方法（Rietveld MEM）的组合，这是一种非常强大的方法，可以确定富勒烯化合物的确切电荷密度分布。例如，它可以使结构变体的灵活性有时在富勒烯化合物中出现;就像单个原子的Hemispherical Distribution一样。By using RietveldMEM， accurate electron density distributions were obtained for Sc@CイD282イエD2， ScイD22イイD2@CイD2， ScイD23イD2@CイD282イD2 and some others。The most surprising result was that encapsulated three Sc atoms formed triangular cluster in ScイD23エD2@CイD282エD2。对于碱性富勒烯，发现了它，因为在电荷转移和过渡温度之间存在明确的关系， Tc，即电荷转移到富勒烯笼增加， Tc增加。

There are three aims of this study. They are 1) to establish the accurate structure analytical method for fullerene compounds, 2) to find out the accurate structure of endohedral metallo-fullerene compounds at electron level and 3) to have better understanding of the relationships between superconductivity of alkalidope fullerene compounds and their structural characteristic. First of all, it was found out that the combination of Rietveld refinements and the Maximum Entropy Method (RietveldMEM) was a very powerful method to determine accurate charge density distribution of fullerene compounds. For example, it can allow flexibility of structural varieties sometimes occurred in fullerene compounds ; such as hemispherical distribution of a single atom. By using RietveldMEM, accurate electron density distributions were obtained for Sc@CィイD282ィエD2, ScィイD22ィエD2@CィイD284ィエD2, ScィイD23ィエD2@CィイD282ィエD2 and some others. The most surprising result was that encapsulated three Sc atoms formed triangular cluster in ScィイD23ィエD2@CィイD282ィエD2. For alkalidope fullerene, it was found out that there was clear relationship between charge transfer and transition temperature to superconductors, Tc, that is as charge transfer to fullerene cage increased, Tc increased.