Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 78: Electronic Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - V
O 78.9: Talk
Wednesday, March 22, 2017, 17:00–17:15, GER 38
Local density fitting within a Gaussian and plane waves scheme for large-scale density functional theory calculations — •Dorothea Golze1,2, Marcella Iannuzzi1, and Jürg Hutter1 — 1Aalto University, Otakaari 1, 02150 Espoo, Finland — 2University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
A local resolution-of-identity (LRI) approach is introduced in the Gaussian and plane waves (GPW) scheme to enable large-scale Kohn-Sham (KS) density functional theory calculations. The construction of the KS matrix in GPW scales already linearly with respect to system size by using a plane wave expansion of the density for the evaluation of the Coulomb term in combination with a local basis. The intention is to retain the linear scaling of the GPW approach, while reducing the prefactor for computing the KS matrix. The locality of the density fitting ensures an O(N) scaling and is implemented by approximating the atomic pair density by an expansion in one-center fit functions. The prefactor is smaller with LRI since the computational demands for the grid-based operations become negligible, while they are dominant in GPW. We observe a speed-up of the self-consistent field (SCF) procedure by a factor of up to 30 for periodic systems dependent on the symmetry of the simulation cell and the grid cutoff. The accuracy of LRIGPW is assessed for different systems and properties. Generally, total energies, reaction energies, intramolecular and intermolecular structure parameters are well reproduced. LRIGPW yields also high quality results for extended condensed phase systems such as liquid water, ice XV and molecular crystals.