Molecular dynamics simulations of formation of metal-containing fullerene

Abstract

The growth process of metal-containing fullerene was studied by using the molecular dynamics method. Based on DFT (density functional theory) calculations of various forms of small clusters MCn (M = La, Ni), multi-body potential functions between carbon and metal atoms were constructed with the Morse-type term and the Coulomb term as functions of coordinate number of a metal atom. The clustering process starting from 500 isolated carbon atoms and 5 metal atoms in a 342 A cubic cell was simulated under the controlled temperature condition at Tc = 3000 K, and the growth history of metal-attached clusters was studied in detail. Fan-type structure was reproduced around the metal atom for MCn (n<5), and mono-cyclic ring or bi-cyclic ring was observed for both La and Ni system. An open cap structure was formed around a lanthanum atom for LaCn (20 < n<50). The lanthanum atom was completely enclosed in the carbon cage at the final stage, though the nickel atom attached on one face of the caged structure.