Prof. Irene Burghardt 

Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max von-Laue Str. 7, 60438 Frankfurt, Germany

Many elementary processes in functional organic materials involve ultrafast photoinduced energy and charge transfer, as highlighted by time-resolved spectroscopic observations. Coherent effects are found to play a major role, despite static and dynamic disorder. Hence, quantum dynamical methods are needed to elucidate the details of these ultrafast transfer events and capture the subtle interplay of site-to-site electronic couplings, exciton and charge delocalization, nonadiabatic effects and vibronic couplings. In this lecture, we review an approach that combines first-principles parametrized Hamiltonians [1], with accurate quantum dynamics simulations using the Multi-Layer Multi-Configuration Time-Dependent Hartree (MCTDH) method [1-4], along with semiclassical approaches [5,6]. The lecture will focus on (i) exciton dissociation and free carrier generation in regioregular donor-acceptor assemblies [1,7], and (ii) the elementary mechanism of exciton migration [5,6,8-10] and creation ofcharge-transfer excitons [7,11] in polythiophene and poly(para-phenylene vinylene) type materials. Special emphasis is placed on the interplay of trapping due to high-frequency phonon modes andthermal activation due to low-frequency ”soft” modes which drive a diffusive dynamics [6,9,10].

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References

[1] M. Polkehn, P. Eisenbrandt, H. Tamura, I. Burghardt, Int. J. Quantum Chem. 118:e25502. (2018).https://onlinelibrary.wiley.com/doi/full/10.1002/qua.25502

[2] M. H. Beck, A. Jaeckle, G.A. Worth, H.-D.Meyer, Phys. Rep. 324, 1 (2000).https://www.sciencedirect.com/science/article/abs/pii/S0370157399000472

[3] G.A.Worth, M. H. Beck, A. Jäckle, H.-D.Meyer, The MCTDH package, University of Heidelberg https://www.pci.uni-heidelberg.de/mctdh

[4] H. Wang, J. Phys. Chem. A 119, 7951 (2015).https://pubs.acs.org/doi/10.1021/acs.jpca.5b03256

[5] R. Liang, S. J. Cotton, R. Binder, I. Burghardt, W. H. Miller, J. Chem. Phys. 149, 044101 (2018).https://aip.scitation.org/doi/10.1063/1.5037815

[6] R. Hegger, R. Binder, and I. Burghardt, J. Chem. Theor. Comput., 16, 5441 (2020).https://pubs.acs.org/doi/10.1021/acs.jctc.0c00351

[7] M. Polkehn, H. Tamura, I. Burghardt, J. Phys. B: At. Mol. Opt. Phys. 51, 014003 (2018).https://iopscience.iop.org/article/10.1088/1361-6455/aa93d0

[8] R. Binder, D. Lauvergnat, I. Burghardt, Phys. Rev. Lett., 120, 227401 (2018).https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.227401

[9] R. Binder, I. Burghardt, Faraday Discuss., 221, 406 (2020).https://pubs.rsc.org/en/content/articlelanding/2020/FD/C9FD00066F#!divAbstract

[10] F. Di Maiolo, D. Brey, R. Binder, and I. Burghardt, J. Chem. Phys., 153, 184107 (2020).https://aip.scitation.org/doi/10.1063/5.0027588

[11] W. Popp, M. Polkehn, R. Binder, I. Burghardt, J. Phys. Chem. Lett., 10, 3326 (2019).https://pubs.acs.org/doi/10.1021/acs.jpclett.9b01105