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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 27: Molecular Electronics and Excited State Properties II
CPP 27.2: Vortrag
Mittwoch, 19. März 2025, 11:45–12:00, H38
Charge transport in organic semiconductors with a mapping approach to surface hopping — •Johan Runeson1, Thomas Drayton2, and David Manolopoulos2 — 1Institute of Physics, University of Freiburg, Germany — 2Physical and Theoretical Chemistry Laboratory, University of Oxford, UK
Coupled charge-phonon systems are challenging to simulate in the intermediate regime between traditional delocalized band theory and localized polaron theory. In particular, it remains unclear which methods are suitable to describe organic semiconductors. Conventional trajectory-based methods, such as Ehrenfest dynamics and surface hopping, do not capture the correct equilibrium of mixed quantum-classical systems. In this talk, I will present a simple solution to this problem. Based on a recently developed ``mapping approach to surface hopping'' [1,2], we propagate trajectories on the adiabatic state with the highest population, which in contrast to previous methods is consistent with the correct quantum-classical equilibrium. We applied this methodology to charge diffusion in crystalline rubrene [3] and obtained a well-defined diffusion constant, without having to introduce the phenomenological relaxation time approximation (RTA). Our results give 30-60 % higher charge mobilities than conventional RTA calculations and shed light on experiments of the optical conductivity.
[1] J. R. Mannouch and J. O. Richardson, J. Chem. Phys. 158, 104111 (2023). [2] J. E. Runeson and D. E. Manolopoulos, J. Chem. Phys. 159, 094115 (2023). [3] J. E. Runeson, T. J. G. Drayton, and D. E. Manolopoulos, J. Chem. Phys. 161, 144102 (2024).
Keywords: Charge transport; Non-adiabatic; Surface hopping; Mixed quantum-classical; Organic semiconductors