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arXiv · 2511.20433

A Vibronic Coupling Model to Study the Nonadiabatic Dynamics of Polyenes

Timothy N. Georges·Louis Summerley·Johan E. Runeson·William Barford
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Abstract

We develop a linear vibronic coupling (LVC) model for polyenes described by the extended Hubbard-Peierls Hamiltonian. This model is applied to trans-hexatriene to benchmark quantum-classical dynamics methods against fully quantum simulations. We find that surface-hopping methods describe short times more accurately than multi-trajectory Ehrenfest. None of the quantum-classical methods studied obtain the long-time population oscillations found in fully quantum simulations. Varying the parameters of the LVC Hamiltonian, we find that surface hopping reproduces the correct trends in the long-time dynamics across a wide range of parameters, but generally overestimates the degree of internal conversion. On the other hand, multi-trajectory Ehrenfest gives more accurate long-time populations in proximity to the hexatriene parameter set.

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Timothy N. Georges, Louis Summerley, Johan E. Runeson, William Barford. 2025-11-25. A Vibronic Coupling Model to Study the Nonadiabatic Dynamics of Polyenes. https://arxiv.org/abs/2511.20433

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