Accurate structure analyses of fullerene compounds by the Maximum Entropy Method

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-I D282-D-D2，Sc-I D22-D 2@C-I D284-D 2，Sc-I D 23-D 2@C-I D 282-D 2 and some others.The most surprising result was that encapsulated three Sc atoms formed triangular cluster in Sc I D 23文件D2@C I D 282文件D 2.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。

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.