Forcing a Molecule to Switch: Quantifying Mechanical Control at the Atomic Scale

Authors

• A. M. Shashika D. Wijerathna, Old Dominion UniversityFollow
• Markus Zirnheld, Old Dominion UniversityFollow
• Michael L. Hildebrand, Old Dominion UniversityFollow
• Myles Perry, Old Dominion UniversityFollow
• Marjorie Cenese, Old Dominion UniversityFollow
• Yuan Zhang, Old Dominion UniversityFollow

Document Type

Article

Publication Date

2026

DOI

10.1021/acs.nanolett.6c01515

Publication Title

Nano Letters

Volume

26

Issue

27

Pages

8661-8670

Abstract

Mechanically induced conformational switching at the single-molecule level represents a fundamental mechanism for molecular functionality, yet quantitative characterization of the underlying force and energy landscape remains limited. Here, we study individual TBrPP-Co(II) molecules on Au(111) using qPlus atomic force microscopy. By reconstructing interaction potentials from 3D Δf(x,y,z) data, we determine a threshold force of ∼96 ± 8 pN and a tip-induced switching interaction energy of ∼38 ± 4 meV associate with the conformational transition. The isolated tip-molecule force follows a power law (exponent ∼6), indicating dominance of long-range van der Waals interactions. At closer distances, deviations reveal force-induced deformation preceding the transition. Validation via the inflection point test confirms measurement reliability. These findings show that long-range dispersive interactions can mechanically deform a molecule and facilitate conformational switching through a deformation-assisted pathway, providing a quantitative framework for controlling mechanically driven functionality at the single-molecule scale.

Rights

© 2026 The Authors. This publication is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) License.

Original Publication Citation

Wijerathna, A. M. S. D., Zirnheld, M., Hildebrand, M. L., Perry, M., Cenese, M., & Zhang, Y. (2026). Forcing a molecule to switch: Quantifying mechanical control at the atomic scale. Nano Letters, 26(27), 8661-8670. https://doi.org/10.1021/acs.nanolett.6c01515

ORCID

0009-0009-9748-6927 (Zirnheld), 0009-0003-5754-7322 (Hildebrand), 0009-0008-5528-0181 (Cenese)

Repository Citation

Wijerathna, A. M. Shashika D.; Zirnheld, Markus; Hildebrand, Michael L.; Perry, Myles; Cenese, Marjorie; and Zhang, Yuan, "Forcing a Molecule to Switch: Quantifying Mechanical Control at the Atomic Scale" (2026). Physics Faculty Publications. 1059.
https://digitalcommons.odu.edu/physics_fac_pubs/1059