Three-dimensional intermolecular force microscopy.

Intermolecular contrast in atomic force microscopy images without intermolecular bonds.

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 con...

Three-dimensional traction force microscopy of engineered epithelial tissues.

Several biological processes, including cell migration, tissue morphogenesis, and cancer metastasis, are fundamentally physical in nature; each implicitly involves deformations driven by mechanical forces. Traction force microscopy (TFM) was initially developed to quantify the forces exerted by individual isolated cells in two-dimensional (2D) culture. Here, we extend this technique to estimate...

Real-space identification of intermolecular bonding with atomic force microscopy.

We report a real-space visualization of the formation of hydrogen bonding in 8-hydroxyquinoline (8-hq) molecular assemblies on a Cu(111) substrate, using noncontact atomic force microscopy (NC-AFM). The atomically resolved molecular structures enable a precise determination of the characteristics of hydrogen bonding networks, including the bonding sites, orientations, and lengths. The observati...

Three-dimensional atomic force microscopy: interaction force vector by direct observation of tip trajectory.

The prospect of a robust three-dimensional atomic force microscope (AFM) holds significant promise in nanoscience. Yet, in conventional AFM, the tip-sample interaction force vector is not directly accessible. We scatter a focused laser directly off an AFM tip apex to rapidly and precisely measure the tapping tip trajectory in three-dimensional space. This data also yields three-dimensional cant...

Computational study of three dimensional potential energy surfaces in intermolecular hydrogen bonding of cis-urocanic acid