A periodic charge-dipole electrostatic model: parametrization for silver slabs

• Published in: The Journal of chemical physics Vol. 137; no. 13; p. 134702
• Main Authors: Bodrenko, I V, Sierka, M, Fabiano, E, Della Sala, F
• Format: Journal Article
• Language: English
• Published: United States 07.10.2012
• Subjects: Quantum Theory; Silver - chemistry; Static Electricity
• ISSN: 1089-7690
• DOI: 10.1063/1.4754719

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.