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CPP 96.8: Vortrag
Donnerstag, 19. März 2020, 16:45–17:00, ZEU 260
Accurate Phonon Calculations in Molecular Crystals: The Instructive Case of Naphthalene — •Tomas Kamencek1,2, Sandro Wieser1, Natalia Bedoya-Martínez3, Johannes P. Dürholt4, Rochus Schmid4, and Egbert Zojer1 — 1Institute of Solid State Physics, Graz University of Technology, Austria — 2Institute of Physical and Theoretical Chemistry, Graz University of Technology, Austria — 3Materials Center Leoben, Austria — 4Chair of Inorganic Chemistry 2, Ruhr University Bochum, Germany
Over the past decades the properties of molecular crystals have been studied extensively to improve the performance of organic electronic devices. Many of the materials properties relevant in this context are crucially affected by phonons. For example, strong electron-phonon coupling is a limiting factor for charge transport in molecular crystals, and entropic contributions from phonons play a decisive role for the relative stability of polymorphs. The simulation of phonon band structures with ab initio methods like dispersion-corrected density-functional theory, however, poses a sizable challenge for all but the simplest systems. Therefore, here we test the suitability of more approximate methods, which can be applied not only to simple systems, but also to practically relevant materials. These methods comprise density-functional tight binding and various classical force fields (FFs). Besides transferable FFs of varying sophistication (GAFF and COMPASS) we tested MOF-FF which was specifically parametrized for our benchmark system. As the latter we chose deuterated naphthalene, for which phonon band structures have also been studied experimentally.