Volume 124, 2003

Multipoles and interaction potentials in ionic materials from planewave-DFT calculations

Abstract

Oxide potentials which transfer well between different materials have to account explicitly for many-body contributions to the interaction potentials between the ions. These include dipole and quadrupole polarization effects and the compression and deformation of an oxide ion by its immediate coordination environment. Such complex potentials necessarily involve many parameters. We examine how the results of ab initio electronic structure calculations, based upon planewave DFT methods, on general configurations of ions derived from simulations at finite temperature, may be used to parameterize an “aspherical ion method” (AIM) potential (A. J. Rowley, P. [J with combining umlaut]emmer, M. Wilson and P. A. Madden, J. Chem. Phys., 1998, 108, 10 209). Dipoles and quadrupoles on the individual ions are obtained via a transformation of the Kohn–Sham orbitals to localized orbitals on each ion, which enables a distorted charge density for each ion to be obtained. The dipoles and quadrupoles appearing in polarization parts of the AIM potential are fit to those obtained from the ab initio ionic charge densities obtained in this way. The remaining parts of the potential, describing short-range repulsive interactions between ions with compressed and deformed charge densities, are fit to the ab initio forces and the stress tensor. By using a sufficiently large and varied set of configurations on which to carry out this optimization, an excellent transferable potential is obtained.

Article information

Article type
Paper
Submitted
09 Jan 2003
Accepted
24 Jan 2003
First published
06 Jun 2003

Faraday Discuss., 2003,124, 171-184

Multipoles and interaction potentials in ionic materials from planewave-DFT calculations

A. Aguado, L. Bernasconi, S. Jahn and P. A. Madden, Faraday Discuss., 2003, 124, 171 DOI: 10.1039/B300319C

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