title: Quantifying molecular stiffness and interaction with lateral force microscopy.
abstract: The spatial resolution of atomic force microscopy (AFM) can be drastically increased by terminating the tip with a single carbon monoxide (CO) molecule. However, the CO molecule is not stiff, and lateral forces, such as those around the sides of molecules, distort images. This issue begs a larger question of how AFM can probe structures that are laterally weak. Lateral force microscopy (LFM) can probe lateral stiffnesses that are not accessible to normal-force AFM, resulting in higher spatial resolution. With LFM, we determined the torsional spring constant of a CO-terminated tip molecule to be 0.24 newtons per meter. This value is less than that of a surface molecule and an example of a system whose stiffness is a product not only of bonding partners but also local environment.
authors: Universität Regensburg, Regensburg 93053, Germany.
authors: Alfred John
authors: AJ
authors: Weymouth
authors: Thomas
authors: T
authors: Hofmann
authors: Franz J
authors: FJ
authors: Giessibl