SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 79: Focus Session: Frontiers of Electronic-Structure Theory VI (joint session O/HL)

O 79.6: Vortrag

Donnerstag, 30. März 2023, 12:15–12:30, TRE Ma

Anharmonic Fingerprints from THz Modes of Polyacene Crystals — •Paolo Lazzaroni, Shubham Sharma, and Mariana Rossi — Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

Organic molecular crystals exhibit strong lattice anharmonicity, especially in the collective motions that are governed by intermolecular interactions and lie in the low-frequency THz range [1]. Inspired by recent observations that the polarization-orientation (PO) Raman spectra can give exquisite insight into the anharmonic couplings between modes [2], we devise a first-principles framework that can reproduce, explain and give quantitative insight into the type and strengths of mode coupling. This framework is based on machine-learned potentials and polarizability tensors trained on ab initio molecular dynamics trajectories [3]. We obtain results through the time-correlation formalism for PO Raman signals, retaining the full anharmonic nature of the potential, and perform a novel analysis of effective temperature-dependent mode couplings from our trajectories. [1] M. Asher et al., Adv. Mater. 32, 1908028 (2020) [2] N. Benshalom et al., arXiv:2204.12528 (2022) [3] N. Raimbault et al., New J. Phys. 21 105001 (2019)