The Effects of Encapsulated Fullerene on Dynamical Properties of a Peapod

Abstract

Mechanical properties of fullerene encapsulated nanotubes called peapods are theoretically investigated. We compared two models of the peapods in which inter-molecular forces are estimated by the ab initio calculation or by the Lennard-Jones potential. The former model concludes stiffening in every vibrational normal mode, but the latter shows softening. Although stiffness change depends on the model, we are able to extract general tendency of each specific mode. The encapsulation tends to stiffen the compressing modes and radial breathing mode (RBM), while the bending mode and the stretching mode may be softened by the encapsulation, if fullerenes and a tube attract with each other.