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