  Intermolecular features in atomic force microscopy (AFM) 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 AFM 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.
