Polarization-density-based electron density modeling of metal surfaces

Abstract

Describing a metal-solution interface is one of the major interests in many applications, for example, energy storage devices, catalysts, and therapeutics. For the adsorption of biomolecules with considerable dipole moments the surface polarization is not negligible. However, the consideration of polarization effects at metal surfaces requires quantum mechanical calculations, which demand high computational costs. In this work, we developed a method to create an electron density map of a metal surface by employing the concept of polarization density. Based on the results from density functional theory (DFT) methods, we pre-defined a polarizability tensor field on a rectangular real-space grid. The polarizability tensor field adequately describes polarization density, electron density, and electrostatic stabilization energy induced by an external charge close to the metal surface. The advantage of our method is that we can get a map of electron density without repetitive quantum mechanical calculations. Therefore, the method we suggested readily extends to introduce polarization effects to molecular dynamics simulations of metal-solution interfaces, with minimal extra computational costs.