Optimized interaction parameters for metal-doped endohedral fullerene

Abstract

Interaction between various atoms doped inside C 60 can be modeled using interaction potentials and, thus, cohesive energy and other physical constants may be calculated. In case of metal-doped fullerene total energy may be written in terms of three different types of interactions, namely carbon-carbon interaction, metal-metal interaction and carbon-metal interaction. Brenner potential, Gupta potential, and Lennard-Jones potentials have been used to model these interactions respectively. Generally, parameters used in these model potentials are not readily available and need to be fine-tuned for different dopants. In this paper, we have deduced/optimized these interaction parameters for Cu, Ag, Al and Ga doped C 60 comparing with our Density Functional Theory (DFT) results and hence predicting the stability of various metal-doped fullerenes. Total energy calculations reveal that a maximum of nine copper atoms can be doped inside the fullerene cage and form stable complex without distorting the cage significantly. As we add more number of Cu atoms in the fullerene molecule, cage structure breaks down. In the same way, we have done calculations for Ag, Al and Ga atoms doped inside the fullerene molecule and found that the maximum of eight, nine, nine atoms can form stable complexes.