Structural Study of Endohedral Mtallaofullerenes encapsulated in peapod.

包裹在富勒烯笼子中的金属原子的分子结构和成键性质是关系到金属富勒烯内部结构的稳定性和包裹金属富勒烯的豆荚的重要结构信息。利用最大熵方法(MEM)，用同步辐射(SR)粉末衍射法研究了金属富勒烯的电荷密度。首次测定了体内金属富勒烯(Gd@C_&lt；82&gt；，La_2@C_&lt；80&gt；，Y_2@C_&lt；82&gt；，Y_2C_2@C_&lt；84&gt；，)。金属富勒烯的精确MEM电荷密度揭示了金属原子与碳笼之间离子和共价键的存在，以及碳笼内金属原子的热运动特征。MEM/Rietveld方法是利用纳米多孔材料强大的结构分析技术进一步发展起来的，是确定富勒里德结构的数据分析的关键方法。

The molecular structure and bonding nature of metal atoms encapsulatd in fullerene cage is important structural information relating to stability of metallofullerene endohedral structure and the metallofullerene encapsulating peapods. The experimental charge density studies of endohedral metallofullerenes by the Synchrotron Radiation (SR) powder diffraction utilizing the Maximum Entropy Method (MEM) were carried out. Results of the endohedral metallofulleres (Gd@C_<82>, La_2@C_<80>, Y_2@C_<82> and Y_2C_2@C_<84>, ) were determined for the first time. The precise MEM charge densities of the metallofullerenes reveal existence of ionic and/or covalent bonding between metal atoms and carbon cage as well as the feature of thermal motion of metal atoms inside the carbon cage. The MEM/Rietveld method, which is the crucial methods for data analysis in order to determine endohedral structure of the fulleride, were further developed for the powerful structure analysis technique of nano-porous materials.