Theory Study On Endohedral Metallofullerence La₂@C₈₀(I_h) And PrSc@C₈₀

Due to the fact of the special structure and great potential applications, metallofullerenes have being attracted intense attentions of chemistry, materials sciences and condensed matter physics, especially the fancy dynamic character. In this thesis, we study M2@C80, including the motion of the metals in La2@C80 and PrSc@C80, the bimetallic endohedral fullerene contained different metals.Molecular dynamics simulation and all-electron relativistic density functional computations are performed to study the motion of metal atoms in La2@C80.Fristly we use the interaction of C-La, La-La on all-electron relativistic density functional computations to describe the motion of metal atoms. Lennard-Jones potential is also applied to describe the interaction of C-La, La-La respectively. A reasonable force field was builted by Lennard-Jones potential and electrostatic potential. By fitting force field from the ground state of La2@C8o(Ih), the steady structure, height of energy barrier, frequencies, potential energy curves of La2@C80, and the electrostatic interactions, we obtained a more reasonable force field. Besides, we obtain atomic electronegativity and atomic hardness parameters of La2@C80.We introduce the EEM algorithm to the common used MD software suite so that the MD simulations can be performed under floating charge force field. The motion image of La atom were obtained by this method in CS2 at T=300K.The structural characteristic of PrSc@C80 has been investigated by the all-electron relativistic density functional computations, also for the ab initio molecule dynamics simulated. These study show that the symmetry of the most stable cage is D5h, and the metal atoms Pr and Sc is on C2v axis. The stable distance of Pr and Sc is 3.709A. The result of dynamics also shows that the metals don't move which could further explain the C2v symmetry of PrSc@C80. This conclusion corresponds with the experimental NMR spectrum. A far rarer form of endohedral fullerene is where the entrapped species consists of two different metal atoms. The production of PrSc@C80 in high purity has enabled the characterization of a bimetallic endohedral fullerene.