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O: Fachverband Oberflächenphysik

O 77: Nanostructures at surfaces:1D, 2D, networks II

O 77.2: Vortrag

Donnerstag, 12. März 2026, 10:45–11:00, HSZ/0204

Revealing and manipulating correlated protons in one-dimensional hydrogen-bonded chains at the atomic scale — •Yiqi Zhang — Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

Hydrogen-bonded systems such as water and ice exemplify highly cooperative proton dynamics, where covalent bonds are broken and formed in a concerted fashion. Yet directly probing and controlling many-body proton configurations at the atomic scale remains challenging. Here, using bond-resolved atomic force microscopy and spectroscopy, we reveal multistate proton ordering in self-assembled one-dimensional chains of an imidazole derivative on a noble metal surface. In as-grown chains of varying length, we consistently identify an interior species bonded to an extra proton, forming a localized imidazolium cation (state 1). Selective removal of a single proton from either chain end triggers a collective rearrangement of protons, yielding unidirectional hydrogen-bonding along the entire chain (states 2 or 3). Further deprotonation creates a proton vacancy, enabling reversible switching of hydrogen-bonding directionality (states 4 and 5) via collective proton hopping above a threshold bias voltage. In conjunction with density functional theory calculations, we elucidate the microscopic origin of complex proton ordering in hydrogen-bonded chains and the correlated motion of multiple protons.

Keywords: atomic force microscopy; atomic force spectroscopy; hydrogen bonds; proton ordering; correlated proton motion