Vibrational Excitation Mechanism in Tunneling Spectroscopy beyond the Franck-Condon Model
Gaël Reecht, Nils Krane, Christian Lotze, Lei Zhang, Alejandro L. Briseño, Katharina J. Franke
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.
Topics & Concepts
Vibronic spectroscopySpectral lineScanning tunneling microscopeExcitationQuantum tunnellingSpectroscopyMoleculeAtomic physicsVibronic couplingFranck–Condon principleMolecular physicsMaterials sciencePhysicsExcited stateCondensed matter physicsQuantum mechanicsMolecular Junctions and NanostructuresQuantum and electron transport phenomenaSurface Chemistry and Catalysis