Dresden 2026 – scientific programme
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O: Fachverband Oberflächenphysik
O 45: Organic molecules on inorganic substrates: Adsorption and growth – Poster
O 45.7: Poster
Tuesday, March 10, 2026, 14:00–16:00, P2
Force mapping of a pyridyl-functionalized platform molecule by noncontact atomic force microscopy — •Hyeji Choi1, Behzad Mortezapour2, Martin Wolf1, Richard Berndt2, and Akitoshi Shitotari1 — 1Fritz-Haber Institute of the Max-Planck Society, Berlin, Germany — 2Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
Platform molecules based on trioxatriangulenium (TOTA) form triangular adsorption motifs on metal surfaces with a functional group protruding to the vacuum [1]. However, probing the atomic-scale structure of such steric molecules remains challenging. Here, we study pyridyl-TOTA on Ag(111) and perform single-molecule force mapping, using noncontact atomic force microscopy (NC-AFM) at 6 K. We obtained force and potential maps of the pyridyl group interacting with a metal tip by measuring frequency shift as a function of tip height and location. These maps reveal anisotropy depending on the direction relative to the pyridyl ring plane. Simulations using Lennard-Jones potential reproduce the map appearances, enabling estimation of the preferred ring orientation and directional stiffness. We thus demonstrate the high potential of single-molecule force mapping for the structural characterization of steric adsorbate.
[1] Mortezapour, B., et al., ACS Nano 19, 38773-38780 (2025)
Keywords: non-contact Atomic Force Microscopy (ncAFM); Scanning Probe Microscopy; Tip-molecule interaction; Interatomic force measurement