Relativistic Density Functional Study On Lu₂＠C₇₆ And La＠C₈₂

Endohedral metallofullerenes (EMFs) have attracted much attention because of the unique structure and properties. These properties lead that they could be of wide use in many different fields, such as materials science, biology, medicine, etc. Relativistic density functional theory is the only first principle of relativity multi-body theory method that can be used for complex macromolecular system so far. In this paper, the geometrical structures, metal motion as well as spectrum features of Lu2@C76 (Td) and La@C82(C2v) have been investigated by means of relativistic density functional computations.Relativistic density functional calculations were performed for Lu2@C76(Td) using two methods, the zero-order regular approximation (ZORA) basis sets in ADF package and all electron relativistic core treatment in Dmol3 code. The configurations of different isomers have been explored using representative patch analysis method. The results show that the most stable isomer has C2 symmetry. The transition state between C2 isomers has been found, which discloses that the barrier energy for the motion of Lu atoms between the stable points is 3.18 kcal/mol. The motion trajectory has an Oh symmetry, in accordance with the STM image. We have also calculated the 13C NMR spectrum of the molecule with the trajectory, which is in an excellent agreement with the experimental nuclear magnetic resonance (NMR) spectrum. Further, we find a rule that the symmetries of EMFs are determined by the symmetry of carbon cage and called it "carbon cage determining rule ".The interaction between lanthanum atom and Cs2(C2v) has been investigated by all electron relativistic core treatment in Dmol3 code. Geometry optimization was done for La@C82. We investigate the interaction between La and different key points on Cs2(C2v) representative patch, and get the potential energy curve of La@C82. Infrared absorption spectra was computed to assist experimental characterization. Geometry optimization for M@ v,M= Lanthanide) were also performed.