Visualizing the orientational dependence of an intermolecular potential.

Adam Sweetman,Mohammad A Rashid,Philipp Rahe,Philip Moriarty,Janette L Dunn,Samuel P Jarvis

doi:10.1038/ncomms10621

Adam Sweetman, Mohammad A Rashid + Show 4 more

Open Access

https://doi.org/10.1038/ncomms10621

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Journal: Nature Communications	Publication Date: Feb 16, 2016
Citations: 12	License type: CC BY 4.0

Affiliation: University of Nottingham

Abstract

Scanning probe microscopy can now be used to map the properties of single molecules with intramolecular precision by functionalization of the apex of the scanning probe tip with a single atom or molecule. Here we report on the mapping of the three-dimensional potential between fullerene (C60) molecules in different relative orientations, with sub-Angstrom resolution, using dynamic force microscopy (DFM). We introduce a visualization method which is capable of directly imaging the variation in equilibrium binding energy of different molecular orientations. We model the interaction using both a simple approach based around analytical Lennard–Jones potentials, and with dispersion-force-corrected density functional theory (DFT), and show that the positional variation in the binding energy between the molecules is dominated by the onset of repulsive interactions. Our modelling suggests that variations in the dispersion interaction are masked by repulsive interactions even at displacements significantly larger than the equilibrium intermolecular separation.

Highlights

Scanning probe microscopy can be used to map the properties of single molecules with intramolecular precision by functionalization of the apex of the scanning probe tip with a single atom or molecule
Three-dimensional (3D) force maps were acquired over planar organic molecules that bore a striking resemblance to the classic textbook ‘ball-and-stick’ models. These advances were first realized via the controllable functionalization of the scanning probe tip with a single pre-selected atom or molecule, which provides a unique level of control with which to investigate the atomic and molecular scale properties of matter, and helps to eliminate the most troublesome aspect of scanning probe experiments, that is, the uncertainty surrounding the tip structure
This tip functionalization strategy is commonly applied to single CO molecules to allow intramolecular imaging[1,2], the technique has application well beyond imaging, and similar protocols have been used to study the electronic[3,4] and mechanical[5] properties of single molecules trapped in the tip-sample junction, and to quantitatively measure intermolecular interactions[6,7,8]

Summary

Introduction

Scanning probe microscopy can be used to map the properties of single molecules with intramolecular precision by functionalization of the apex of the scanning probe tip with a single atom or molecule. Three-dimensional (3D) force maps were acquired over planar organic molecules that bore a striking resemblance to the classic textbook ‘ball-and-stick’ models These advances were first realized via the controllable functionalization of the scanning probe tip with a single pre-selected atom or molecule, which provides a unique level of control with which to investigate the atomic and molecular scale properties of matter, and helps to eliminate the most troublesome aspect of scanning probe experiments, that is, the uncertainty surrounding the tip structure.

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Conclusion