Freiburg 2024 – scientific programme

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MO: Fachverband Molekülphysik

MO 20: Theoretical Molecular Physics

MO 20.7: Talk

Thursday, March 14, 2024, 16:00–16:15, HS 3042

Molecular motion enhanced excitation transport in molecular aggregates despite internal molecular vibrations — •Ritesh Pant¹, Varadharajan Srinivasan², Alexander Eisfeld¹, and Sebastian Wüster² — ¹Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — ²Indian Institute of Science Education and Research, Bhopal, India

Molecular aggregates can under certain conditions transport electronic excitation energy over large distances due to the long range dipole-dipole interactions [1]. It was shown earlier that the thermal centre-of-mass motion of molecules can enhance the efficiency of transport compared to the static case in the presence of diagonal disorder, when neglecting molecular vibration [2]. Our current research extends this understanding by examining the impact of molecular vibrations, with a particular focus on adiabatic excitation transport. To simulate quantum dynamics of the electronic excitation coupled to vibrations we use non-Markovian quantum state diffusion, solved through the hierarchy of pure states, combined with classical molecular dynamics for centre-of-mass motion of molecules [2, 3]. Using a specific model of torsional molecular motion, we can identify parameter regimes in which the motion aids excitation transfer even in the presence of vibrations, although adiabatic transport appears disrupted by vibrations.

[1] T. Brixner et. al., Adv. Energy Mater. 7, 1700236 (2017). [2] R. Pant et. al., Phys. Chem. Chem. Phys. 22, 21169 (2020). [3] D. Suess et. al., Phys. Rev. Lett. 113, 150403 (2014).

Keywords: Molecular aggregates; Exciton; Energy transport; NMQSD; Intramolecular vibrations