Probing molecular vibrations by monochromated electron microscopy

Chemical bonds fundamentally determine molecular properties and are prevalently characterized by various spectroscopic means such as infrared and Raman spectroscopies. However, the spatial resolution of these conventional approaches is insufficient to reveal nanoscale features. Recently, monochromated electron energy-loss spectroscopy (EELS) in the transmission electron microscope achieved a groundbreaking energy resolution of a few millielectronvolts and enabled direct observation of molecular vibrational spectrum with unmatched spatial resolution. Vibrational EELS is widely applicable to both organic and inorganic matter in the solid state or liquid phase. In this review, we introduce recent advancements and key concepts of this method, compare with other spectroscopic techniques, and discuss future developments for potential applications in research fields centered on catalysts, polymers, and live cells.

Automated summary

Vibrational EELS is a groundbreaking spectroscopic technique with unmatched energy resolution and spatial resolution, suitable for both organic and inorganic matter in solid state or liquid phase. This review introduces recent advancements and key concepts of the method, compares with other spectroscopic techniques, and discusses future potential applications in research fields centered on catalysts, polymers, and live cells.