Inner workings of a single molecule

Raman spectroscopy is widely used to identify molecules by detecting their signature molecular vibrations. The technology has been refined to be effective at the single-molecule level by making use of strong localized plasmonic fields that can enhance spectral signals. This study goes further, with the demonstration of a technique related to 'tip-enhanced Raman scattering' (TERS) that allows precise tuning of the plasmon resonance and Raman spectral imaging with a spatial resolution below 1 nm, resolving even the inner structure of a single molecule and its configuration on the surface. The technique opens a new path to photochemistry at the single-molecule level, offering the potential to design, control and engineer the functionality of molecules on demand.