Researchers at UCI have developed a 3D imaging technique with sub-nanometer resolution, which allows for imaging of individual bonds within molecules. Visualization and measurements taken at this resolution provide new and profound information about the fundamental aspects of atomic structures and their consequences on chemical activity.
High resolution imaging techniques have become an important tool in the recent push toward single molecule and bond imaging. As a typical molecule is on the order of ~1 nanometer (nm) in size, imaging its individual bonds requires a spatial resolution on the sub-nm scale. Traditional imaging methods are based in optical microscopy which uses focused visible light, but these suffer from an inherent limitation on achievable resolution imposed by the diffraction limit. For example, for light midway within the visible regime (~500 nm), the highest resolution capable under the diffraction limit is on the order of 100 nm. Modifications to both the illumination source and detection mechanism in optical microscopes have allowed for spatial resolutions on the order of 10 nm to be realized; these methods, however, are highly sample-specific and therefore limited in their applications. The imaging of individual bonds therefore necessitates a more general and higher resolution method than optical microscopy.
Researchers at UCI have demonstrated a mechanism for isolating the location of single bonds within a molecule that instead relies on very strong electric fields for imaging. The shifts in the molecular vibrations are extremely sensitive to the electric field position, such that an individual bond can be located with 0.1 nm accuracy. This technique has important implications in single molecule studies, where isolation and monitoring of single bonds is crucial.
§ Molecular bond imaging technique that uses strong field gradients to map out molecular vibrations
§ Higher resolution (0.1 nm) than standard optical microscopy techniques (100 nm) and force microscopy techniques (5 nm)
§ Method is general and customizable: both excitation and vibration detection methods are highly variably
In development. Inventors have determined the experimental parameters necessary (applied field strength, lateral displacement of tip from the sample, etc.) and have modeled how a typical image will appear.