Dresden 2009 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

O: Fachverband Oberflächenphysik

O 41: Ab-initio approaches to excitations in condensed matter I

O 41.7: Talk

Wednesday, March 25, 2009, 16:30–16:45, SCH 251

Exact Kohn-Sham potential of strongly correlated finite systems — •Nicole Helbig, Ilya Tokatly, and Angel Rubio — Nano-Bio Spectroscopy group and ETSF, Dpto. de Física de Materiales, Universidad del País Vasco and Centro Mixto CSIC-UPV/EHU, San Sebastián, Spain

The description of strongly correlated systems within density functional theory has proven very difficult in the past. The dissociation of molecules, even the most simple hydrogen molecule, cannot be described accurately with any of the presently available density functionals. These problems have led to a discussion of what properties the local Kohn-Sham potential has to satisfy in order to correctly describe strongly correlated systems. We use a one-dimensional, two electron model system to investigate the behavior of the exact Kohn-Sham potential, which can be calculated easily for this system. We present an analytic expression for the potential at the dissociation limit and show that the numerical calculations indeed approach and reach this limit as we dissociate the system. It is shown that the functional form of the Kohn-Sham potential is independent of the details of the system under consideration making the results easily transferable to other systems. We use this knowledge to calculate the exact Kohn-Sham potential of the hydrogen molecule in the dissociation limit.