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Updated: Dec 25, 2025

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Vibrational Excitation Mechanism in Tunneling Spectroscopy beyond the Franck-Condon Model
Gaël Reecht1, Nils Krane1, Christian Lotze1
1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
Abstract:
Vibronic spectra of molecules are typically described within the Franck-Condon model. Here, we show that highly resolved vibronic spectra of large organic molecules on a single layer of MoS_{2} on Au(111) show spatial variations in their intensities, which cannot be captured within this picture. We explain that vibrationally mediated perturbations of the molecular wave functions need to be included into the Franck-Condon model. Our simple model calculations reproduce the experimental spectra at arbitrary position of the scanning tunneling microscope's tip over the molecule in great detail.
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