title: Electron beam stimulated molecular motions.
abstract: 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 C(60)'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.
authors.affiliation: Key Laboratory for Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Ke
authors.initials: K
authors.lastname: Ran
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zuo
authors.forename: Qing
authors.initials: Q
authors.lastname: Chen
authors.forename: Zujin
authors.initials: Z
authors.lastname: Shi