Dresden 2026 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 99: Spins on surfaces at the atomic scale III

O 99.12: Vortrag

Freitag, 13. März 2026, 12:15–12:30, WILL/A317

Dark state formation in a zero-field split molecular triplet — •Maria Steiner and Andrea Donarini — Institute of Theoretical Physics, Regensburg University, Regensburg, Germany

In analogy to atomic physics [1], we propose a protocol to prepare and probe a dark state in a single molecule. To this end, we coherently manipulate with a multifrequency magnetic field a three-level system in the V-configuration. Thus, within a density-matrix formalism for open systems, we extend existing protocols developed to probe Rabi oscillations in ESR-AFM on pentacene [2]. The dissipative dynamics of the reduced density matrix are interpreted in terms of multipole expansion and visualized using three intertwined Bloch spheres. We consider a molecule with a zero-field splitting of the first excited triplet. This splitting typically arises from the spatial anisotropy of the frontier orbitals and the spin dipole-dipole interaction between the unpaired electrons. Pentacene is an archetypal example, which, in addition to these properties, also exhibits anisotropic decay to the ground state singlet [3] and thus enables experimental readout of the occupied state [2]. We consider both ideal scenarios and realistic parameterization for ESR-AFM on pentacene to model the expected dark state signature.

[1] Arimondo and Orriols, Lett. al Nuovo Cim. 17, 333 (1976).

[2] Sellies et al., Nature 624, 64 (2023).

[3] Peng et al., Science 373, 452 (2021).

Keywords: dark state; ESR-AFM; single molecules; zero-field splitting