Remote sensing of molecular vibrations with a scanning tunneling microscope (STM) tip. Pechenezhskiy et al. illuminate molecules on a gold substrate by a tunable infrared laser. When the illumination is resonant with a particular vibrational mode, the excitation is transferred to the substrate. This, in turn, causes the surface to shake, which is detected by variations in the tunneling current through the STM tip. As the laser frequency is changed, the STM signal maps out the vibrational spectrum.