Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 10: Methods: Electronic structure theory & Methods: other (theory)
O 10.5: Vortrag
Montag, 22. März 2010, 16:00–16:15, H31
Real-Space DFT for large Molecules on Surfaces — •Paul Baumeister1, Daniel Wortmann1, Tomoya Ono2, and Stefan Blügel1 — 1Institut für Festkörperforschung & Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich — 2Dept. of Precision Science and Technology, Osaka University, Japan
Electronic structure calculations within the framework of density functional theory (DFT) has turned out to be the most powerful tool for a reliable determination of ground state properties of large structures such as big organic molecules on surfaces. Especially complicated systems containing far beyond several hundreds of atoms become move with increasingly into the focus of research. We present a real-space grid density functional simulation code that has been developed in Osaka and Jülich. It combines the flexibility of arbitrary boundary condition with the strength of nearly perfect parallel efficiency on massively parallel computers. The projector augmented wave (PAW) method, proposed by Blöchl[1], provides an accurate description for reproducing the chemical behavior of valence states with a reasonable number of grid points. Grid based methods tend to show Pulay-like forces depending on the atomic position with respect to the nearest grid points, sometimes referred to as egg-box effect. These oscillations of forces and total energies endanger the reliable convergence of structural relaxation. We will discuss how to apply the double grid technique[2] and pre-filtering in Fourier space to avoid this problem.
[1] P.E. Blöchl, PRB 50, 17953 (1994)
[2] T. Ono, K. Hirose, PRB 72, 085115 (2005)