Computation of the static polarizabilities of multi-wall carbon nanotubes and fullerites using a Gaussian regularized point dipole interaction model

A Gaussian regularized dipolar model has been developed for carbon sp2 structures. It is based on three parameters: the two components of the local polarizability tensor of the carbon atoms and a regularization parameter related to the size of the electronic clouds. The parameters of the model have been adjusted to reproduce the polarizability of isolated and FCC aggregates of C60 and C70 molecules, while avoiding any polarization catastrophes. The model has been applied to semiconducting single-wall nanotubes of finite and infinite length. Asymptotically, the axial and transverse polarizability per unit length vary linearly and quadratically with the tube radius, respectively, as already predicted by a tight-binding model and ab initio methods. As for multi-wall nanotubes, we show that the transverse polarizability is close to the transverse polarizability of the external layer taken alone, while the axial polarizability is close to the sum of the axial polarizabilities of the individual layers.