SKM 2021 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 5: Poster Session I

CPP 5.19: Poster

Dienstag, 28. September 2021, 17:30–19:30, P

Towards an accurate calculation of excitation energies of Bacteriochlorophyll complexes with Green’s function-based many-body perturbation theory — •Zohreh Hashemi¹ and Linn Leppert^1,2 — ¹Institute of Physics, University of Bayreuth, Germany — ²MESA+ Institute for Nanotechnology, University of Twente, Netherlands

Bacteriochlorophylls (BCL) are a family of chromophores with key functions in the primary energy-converting processes of bacterial photosynthesis. In vivo, BCLs are embedded in densely packed pigment-protein complexes; an accurate prediction of their electronic structure and excited states is key to understanding their interactions with each other and with their protein environment. However, the sheer size of these complexes, is presently an insurmountable challenge for highly accurate quantum chemical calculations.

Here we present calculations of the optoelectronic properties of BCL monomers and dimers based on first principles Green’s function-based many-body perturbation theory within the GW and Bethe-Salpeter equation (BSE) approach. We find that optical excitations calculated with GW+BSE are in excellent agreement with experimental data and state-of-the-art wavefunction-based approaches - but achieved at considerably lower computational cost than the latter. Our study provides accurate reference results and highlights the potential of the GW+BSE approach for the simulation of larger pigment complexes.