Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 84: Density functional theory and beyond for real materials IV
O 84.7: Talk
Friday, March 26, 2010, 12:45–13:00, H34
An iterative method for TDDFT of large molecules — •Peter Koval1, Dietrich Foerster2, and Olivier Coulaud3 — 1CNRS, INRIA (Hiepacs), Bordeaux, France — 2CPMOH, Bordeaux, France — 3INRIA (Hiepacs), Bordeaux, France
To model the processes in organic solar cells where light first generates an exciton that is then separated at the donor acceptor interface is a challenging task. The first difficulty is the size of the molecules used in such devices and the absence of any translational symmetry. Recently, a fast method for computing of the Kohn-Sham response function [1] in a localized basis set [2] has been developed. The Kohn-Sham response function serves as a building block for TDDFT in linear response, for Hedin’s GW approach and for the Bethe-Salpeter equation. In TDDFT, a drawback of our response function is its large memory requirements. Fortunately, electronic excitation spectra can be computed with an iterative method of moderate computational and memory cost. This method is similar to van Gisbergens iterative method [3] but we use our basis of dominant functions and a more systematic iterative technique (bi-orthogonal Lanczos, GMRES) [4]. In this contribution, we present examples of TDDFT electronic excitation spectra of molecules used in organic photovoltaic.
References [1] D. Foerster, P. Koval., J. Chem. Phys. 131 044103 (2009). [2] D. Foerster, J. Chem. Phys. 128, 034108 (2008). [3] S. J. A. van Gisbergen, C. Fonseca Guerra, E. J. Baerends, J. Comput. Chem. 21, 1511 (2000). [4] Y. Saad, Iterative Methods for Sparse Linear Systems, (Siam, Philadelphia 2003).