Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Poster Session: Correlated Electrons 2

TT 20.11: Poster

Montag, 20. März 2017, 15:00–19:00, P2-OG1

Screened Coulomb interaction for strongly correlated molecular crystals — •Michael M. E. Baumgärtel and Erik Koch — Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich

For strongly correlated molecular crystals we determine screened Coulomb Hubbard-parameters. The unscreened Coulomb interaction of correlated molecular orbitals (MOs) can directly be obtained from Hartree-integrals. This interaction is screened by the electrons in the uncorrelated MOs as these are polarized. We compute the screening due to the self-consistent electric fields arising from the induced distributed dipoles. To treat the polarized crystal, we develop an optimized Ewald summation of the Fourier-transformed dipole-dipole interaction. Employed on a Brillouin zone grid our method yields the screened inter-molecular Coulomb interaction for any charging pattern of the correlated MOs. The optimization of the convergence and performance of our method is demonstrated.

We present the screened Coulomb interaction e.g. for Fullerene crystals and discuss the accuracy and reliability of the results. While in the past only approximations of MOs as a single point-dipole where feasible, we discuss the effect of spacially extended MOs: For example for Fullerenes we approach the limit of point-dipoles by virtually shrinking the Fullerene radius and we determine the renormalization of the polarizabilities due to distribution of the MOs.