Influence of excitonic coupling, static disorder, and coherent dynamics in action-2D electronic spectroscopy of a molecular dimer model

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Autori principali: Bruschi, Matteo, Zambon, Roberto, Gallina, Federico, Fresch, Barbara
Natura: Preprint
Pubblicazione: 2025
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author Bruschi, Matteo
Zambon, Roberto
Gallina, Federico
Fresch, Barbara
author_facet Bruschi, Matteo
Zambon, Roberto
Gallina, Federico
Fresch, Barbara
contents We investigate the spectral features of Action-2D Electronic Spectroscopy (A-2DES) in a molecular dimer model across different regimes of excitonic coupling. By explicitly including a second-excited state for each chromophore, we simulate A-2DES spectra ranging from the non-interacting limit to the strong-coupling case, focusing on the significance of cross peaks. While for weak excitonic coupling, cross peaks can be understood as the incoherent mixing of linear signals of the two chromophores, these features reflect excitonic delocalization as the coupling increases. We highlight that A-2DES offers enhanced sensitivity to coherent excited-state dynamics, particularly in the intermediate-coupling regime, where it provides higher contrast compared to its coherent-detected counterpart. Finally, we show that static disorder reduces the relative amplitude of cross peaks compared to diagonal features in a way that depends on the excitonic coupling. Notably, the relative suppression of cross peaks decreases with the strength of the excitonic coupling, implying that spectral features related to incoherent mixing are less prominent in inhomogeneous samples. These findings support the potential of A-2DES for investigating excitonic dynamics in small multi-chromophoric systems.
format Preprint
id arxiv_https___arxiv_org_abs_2504_10463
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Influence of excitonic coupling, static disorder, and coherent dynamics in action-2D electronic spectroscopy of a molecular dimer model
Bruschi, Matteo
Zambon, Roberto
Gallina, Federico
Fresch, Barbara
Chemical Physics
We investigate the spectral features of Action-2D Electronic Spectroscopy (A-2DES) in a molecular dimer model across different regimes of excitonic coupling. By explicitly including a second-excited state for each chromophore, we simulate A-2DES spectra ranging from the non-interacting limit to the strong-coupling case, focusing on the significance of cross peaks. While for weak excitonic coupling, cross peaks can be understood as the incoherent mixing of linear signals of the two chromophores, these features reflect excitonic delocalization as the coupling increases. We highlight that A-2DES offers enhanced sensitivity to coherent excited-state dynamics, particularly in the intermediate-coupling regime, where it provides higher contrast compared to its coherent-detected counterpart. Finally, we show that static disorder reduces the relative amplitude of cross peaks compared to diagonal features in a way that depends on the excitonic coupling. Notably, the relative suppression of cross peaks decreases with the strength of the excitonic coupling, implying that spectral features related to incoherent mixing are less prominent in inhomogeneous samples. These findings support the potential of A-2DES for investigating excitonic dynamics in small multi-chromophoric systems.
title Influence of excitonic coupling, static disorder, and coherent dynamics in action-2D electronic spectroscopy of a molecular dimer model
topic Chemical Physics
url https://arxiv.org/abs/2504.10463