Electron beam stimulated molecular motions

Electron microscopy with advances in aberration correction has the power to resolve atoms in single molecules. However, its application is limited by electron irradiation induced molecular motions. A better understanding of damage mechanisms is required to achieve the full potential of electron imaging. Here, we report a direct observation of molecular motions stimulated by an electron beam, which allows us to study the breakdown and formation of molecular bonds using C₆₀'s encapsulated inside single-walled carbon nanotubes as a model system. An activation energy of 100 s meV is estimated for the observed molecular motions based on van der Waals interactions. We demonstrate that the molecular confinement can significantly increase the electron energy threshold for breaking the vdW bonds.