Regensburg 2022 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 9: New Methods and Developments: Scanning Probe Techniques 2 (joint session O/KFM)
KFM 9.5: Vortrag
Montag, 5. September 2022, 16:00–16:15, S053
Real-space imaging of σ-hole by means of Kelvin probe force microscopy. — •Aurelio Gallardo1, Benjamín Mallada2, Bruno de la Torre2, and Pavel Jelínek1 — 1FZU of the CAS, Prague, Czech Republic — 2RCPTM-CATRIN, Palacký University, Olomouc Czech Republic
Anisotropic charge distributions on individual atoms, such as σ-holes, are crucial for the structural properties of certain systems. Nevertheless, the existence of σ-holes has only been demonstrated indirectly, either observing the interaction between halogenated molecules or by theoretical calculations. However, there was no experimental technique that would allow the spatail resolution of anisotropic atomic charges.
To tackle this problem, we employed Kelvin probe force microscopy (KPFM) which imaging mechanism relays on the electrostatic tip-sample interaction. To achieve the requested resolution, we developed a theoretical description of the KPFM imaging mechanism on atomic scale, which enables optimize the experimental setup. Namely we demonstrated both theoretically and experimentally that probe tip functionalization by a single Xe atom enhances the spatial resolution to directly visualize the anisotropic charge of the σ-hole, as well as the quadrupolar character of the carbon monoxide molecule. [1]
We believe that this work large already outstanding imaging capabilities of scanning probe techniques. In particular, this KPFM technique will enable better description of charge distribution in molecular complexes as well as on surfaces.
References: [1] Mallada et al., Science 374, 863-867 (2021)