Intermolecular contrast in atomic force microscopy images without intermolecular bonds

Phys Rev Lett. 2014 Oct 31;113(18):186102. doi: 10.1103/PhysRevLett.113.186102. Epub 2014 Oct 31.


Intermolecular features in atomic force microscopy images of organic molecules have been ascribed to intermolecular bonds. A recent theoretical study [P. Hapala et al., Phys. Rev. B 90, 085421 (2014)] showed that these features can also be explained by the flexibility of molecule-terminated tips. We probe this effect by carrying out atomic force microscopy experiments on a model system that contains regions where intermolecular bonds should and should not exist between close-by molecules. Intermolecular features are observed in both regions, demonstrating that intermolecular contrast cannot be directly interpreted as intermolecular bonds.