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O: Fachverband Oberflächenphysik
O 46: Poster Organic Molecules on Inorganic Substrates: Electronic, Optical and Other Properties
O 46.11: Poster
Tuesday, March 18, 2025, 18:00–20:00, P2
Near-field spectroscopy of vibronic states of molecular aggregates — •Sidhartha Nayak1, Fulu Zheng2, and Alexander Eisfeld1 — 1MPIPKS, Dresden, Germany — 2Department of Physics, Ningbo University, Ningbo, China
Strong dipole-dipole interactions between molecules give rise to delocalized electronic excited states in molecular aggregates, which determine their optical properties such as absorption. In near-field spectroscopy, the absorption spectrum of an aggregate is obtained when the molecules interact with electromagnetic radiation that is inhomogeneous across the length of the aggregate. Theoretically, by considering the near-field radiation from the apex of a metallic tip as a source of a localized field, it has been shown that the spectra of the aggregate reveal it’s purely electronic states that are inaccessible through traditional far-field methods [1, 2]. In this contribution, we study aggregates composed of molecules with internal vibrational modes that are strongly coupled to electronic excitations, leading to non-Markovian phenomena. Using a local field method, which is numerically inexpensive, we observe that the vibronic states of aggregates are revealed in the near-field spectra and the spectra are comparable to those obtained by using a more accurate but computationally intensive method [3].
[1] X. Gao and A. Eisfeld, J. Phys. Chem. Lett. 9, 6003 (2018)
[2] S. Nayak, F. Zheng and A. Eisfeld, J. Chem. Phys. 155, 134701 (2021)
[3] D. Suess, A. Eisfeld and W. T. Strunz, Phys. Rev. Lett. 113, 150403 (2014)
Keywords: Near-field spectroscopy; Molecular aggregates; Vibronic states; Exciton; SNOM