Dresden 2017 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 16: Computational Materials Modelling - Novel Materials
MM 16.4: Vortrag
Montag, 20. März 2017, 16:30–16:45, IFW B
Charge transport in organic semiconductors: Towards an ACKS2-based polarizable force field — •Patrick Gütlein1, Lucas Lang1, Karsten Reuter1, Jochen Blumberger1,2, and Harald Oberhofer1 — 1Technische Universität München, Germany — 2University College London, UK
Charge carrier transport, an integral part of diverse reactions and devices, is generally subject to the response of the surrounding environment. Especially in organic semiconductors the accurate theoretical treatment of the electronic rearrangements in the medium is a complex task. The high anisotropy and comparatively low dielectric screening require system sizes that challenge even efficient first-principles approaches like density-functional theory (DFT). In this situation the recently proposed atom-condensed Kohn-Sham density functional theory approximated to second order (ACKS2) approach[1] could represent a computationally undemanding, yet accurate alternative. In this approach, the linear response of the electron density and Kohn-Sham potential are captured by an atom-centered series expansion up to second order. For a range of molecular model systems we systematically compute the ACKS2 parameters with DFT and analyze their dependence on the intra-molecular degrees of freedom. We show that parts of the ACKS2 response can be approximated analytically, with the remaining parameters not varying strongly with respect to molecular motion. This represents an important first step in making ACKS2 applicable as a polarizable force field. [1] T. Verstraelen et al., J. Chem. Phys. 138, 7 (2013); ibid 141, 19 (2014).