ASYMMETRICAL OSCILLATORY MOTION OF ATOMS AND FULLERENES THROUGH OPEN SINGLE-WALLED CARBON NANOCONES

For an open single-walled carbon nanocone, that is, with the cone vertex removed, we examine the oscillatory motion of atoms and fullerenes assumed to be moving along the axis of the cone. The molecular interaction energy is obtained from the 6–12 Lennard–Jones potential using the continuum approximation, which assumes that a discrete atomic structure can be replaced by an average atomic surface density. For the open nanocone, on axis atoms and fullerenes are shown to undergo an asymmetrical oscillatory motion along a path which is both interior and exterior to the nanocone, and with frequencies of oscillation in the gigahertz range. By an asymmetri-cal motion, we mean that the atom or fullerene undergoes an oscillatory motion along the axis of the nanocone such that the acceleration is not simply an odd function of displacement. The present paper constitutes the first identification of an unsymmetrical gigahertz oscillator at the nanoscale, and although even symmetrical oscillators involving nanotubes have yet to be realized experimentally, their theoretical possibility nevertheless remains an important driving force for their practical implementation. 1