title: A periodic charge-dipole electrostatic model: parametrization for silver slabs.
abstract: We present an extension of the charge-dipole model for the description of periodic systems. This periodic charge-dipole electrostatic model (PCDEM) allows one to describe the linear response of periodic structures in terms of charge- and dipole-type gaussian basis functions. The long-range electrostatic interaction is efficiently described by means of the continuous fast multipole method. As a first application, the PCDEM method is applied to describe the polarizability of silver slabs. We find that for a correct description of the polarizability of the slabs both charges and dipoles are required. However a continuum set of parametrizations, i.e., different values of the width of charge- and dipole-type gaussians, leads to an equivalent and accurate description of the slabs polarizability but a completely unphysical description of induced charge-density inside the slab. We introduced the integral squared density measure which allows one to obtain a unique parametrization which accurately describes both the polarizability and the induced density profile inside the slab. Finally the limits of the electrostatic approximations are also pointed out.
authors.affiliation: National Nanotechnology Laboratory (NNL), Istituto Nanoscienze-CNR, Via per Arnesano 16, 73100 Lecce, Italy.
authors.forename: I V
authors.initials: IV
authors.lastname: Bodrenko
authors.forename: M
authors.initials: M
authors.lastname: Sierka
authors.forename: E
authors.initials: E
authors.lastname: Fabiano
authors.forename: F
authors.initials: F
authors.lastname: Della Sala
mesh_terms: D011789:Quantum Theory; D012834:Silver / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D012834:Silver