Potassium orbiting in fullerene based K(C60)2 nanosystem

We have performed a first principle molecular dynamics (MD) simulations for the nanosystem K(C60)2, composed of two fullerene (C60) molecules and one potassium (K) atom. One can observe that at the global minimum of total energy of K(C60)2 nanosystem, the potassium atom is placed exactly between fullerene spheres. Our calculations show that a forced shift of both fullerenes closer to each other leads to substantial change of the shape of global minimum energy. The area of minimal total energy of “squeezed” K(C60)2 forms very characteristic, spatial body (torus). At low temperature (T < 50 K) the potassium atom stays at a particular place inside the minimal total energy torus and performs some small librations. When the temperature raises up to ∼200 K, the potassium “walks” all over the total minimum energy torus. The regular circulation of K atom over the torus-like orbit located between fullerenes results in lack of permanent dipole moment.