Nature of the Weak Bonds: the basis of intermolecular interactions

Single molecules and intermolecular interactions can be probed at unprecedented spatial and energy resolutions with a 600 mK scanning tunneling microscope (STM) in ultrahigh vacuum. Underlying these advances is the development of high resolution vibrational spectroscopy and its offspring - the inelastic tunneling probe (itProbe) at the spatial limit in three dimensions.  These unique capabilities of the STM have provided useful perspectives into the description of the intermolecular chemical bond through real-space visualization of the potential energy surface.