Dynamics of the C60 molecule

Abstract

A characteristic feature of fullerites, just as of the high-temperature cuprates, is the coexistence of the covalent and ionic interactions. These compounds are rather complex, their unit cell contains a lot of atoms. Moreover, realistic models should take into account polarizability of valence bonds under the influence of ionic environment. This may reveal interesting details of the behavior of some modes, as has been demonstrated for Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8}. Hence, the simulation of the dynamics of fullerites requires a reasonably simple model describing, from a single standpoint, both the covalent and ionic interactions and considering the polarizability of valence bonds. Such a model is the adiabatic bond charge model proposed by Weber. It was successfully used in modeling the dynamics of monoatomic compounds of Si, Ge, and C (diamond) and the heteropolar A{sup 3}B{sup 5} semiconductors. It should be noted that the bond charge model was also employed for investigating the vibrations of diatomic and polyatomic molecules. In this paper, Weber`s model has been adapted to the C{sub 60} molecule. Some features of the model inherent in this structure have been discussed. The modeling of the dynamics of C{sub 60} is covered in many papers employing different approaches.more » In some of them good agreement with experiment was obtained. But the authors think the adiabatic bond charge model is more convenient for simulating the dynamics of fullerites. The use of this model will possibly lead to a more precise description of the dynamics of fullerites than in the combined ionic-covalent model employed earlier by the authors.« less