Freiburg 2024 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 7: Poster: Spectroscopy

MO 7.14: Poster

Dienstag, 12. März 2024, 17:00–19:00, Tent C

Decoherence in molecular systems with structured spectral densities studied with Gaussian wavepacket propagation — •Sreeja Loho Choudhury¹, Rainer Hegger¹, Rocco Martinazzo^2,3, and Irene Burghardt¹ — ¹Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Germany — ²Department of Chemistry, Università degli Studi di Milano, Italy — ³Instituto di Scienze e Tecnologie Molecolari, CNR, Milano, Italy

We investigate the time scale of decoherence in complex molecular systems following laser excitation [1]. Vibronic coupling Hamiltonians in conjunction with realistic, structured spectral densities are employed in order to track decoherence on a typical time scale of femtoseconds. Tensor network methods, notably the Gaussian-based Multi-Configuration Time-Dependent Hartree approach [2], are used to obtain accurate decoherence estimates obtained from the time-evolving purity. We focus on a donor-acceptor system that has recently been studied [1], comprising tens of vibrational degrees of freedom. This system is subject to a coherent excitation energy transfer (EET) process and exhibits irreversible decay features despite the finite dimensionality. Numerical decoherence decay is compared with analytical estimates for pure dephasing in spin-boson systems [3-4]. [1] M. Asido et al., Phys. Chem. Chem. Phys. 24, 1795 (2022). [2] P. Eisenbrandt, M. Ruckenbauer and I. Burghardt, J. Chem. Phys. 149, 174102 (2018). [3] O. Prezhdo and P. Rossky, Phys. Rev. Lett. 81, 5294 (1998). [4] M. A. Schlosshauer, Decoherence and the Quantum-To-Classical Transition, Springer (2007).

Keywords: Decoherence; Molecular systems; Gaussian wavepacket propagation; Purity decay; Excitation energy transfer