Abstract
The force exerted on nanoparticles and atomic clusters by fast passing electrons like those employed in transmission electron microscopes are calculated and integrated over time to yield the momentum transferred from the electrons to the particles. Numerical results are offered for metallic and dielectric particles of different sizes ($0--500\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ in diameter) as well as for carbon nanoclusters. Results for both linear and angular momentum transfers are presented. For the electron beam currents commonly employed in electron microscopes, the time-averaged forces are shown to be comparable in magnitude to laser-induced forces in optical tweezers. This opens up the possibility to study optically trapped particles inside transmission electron microscopes.
Highlights
Electromagnetic forces in optical tweezers are currently employed to trap small particles ranging in size from nanometers to several microns,[1,2] and to manipulate them in all spatial directions.[3,4]
We show that the momentum transferred from the passing electrons to the particles can be well below the threshold needed to kick them out for commonly employed trapping laser intensities, a detailed comparison between trapping forces and electron-induced forces suggests that both weak and strong perturbation regimes are possible depending on the distance between the particles and the beam, all of them within the range that allows a sufficiently large electron-particle interaction as to perform electron energy loss spectroscopy (EELS) with significant statistics for in vacuo optically trapped particles
The present work addresses, in a quantitative way, the issue of both linear and angular momentum transfer from an electron beam to small particles. This applies to optically trapped particles, as mentioned above, and to other forms of trapping, like particles deposited on solid substrates, or particles trapped by a tip [e.g., in a scanning tunnel microscope (STM) set up]
Summary
Electromagnetic forces in optical tweezers are currently employed to trap small particles ranging in size from nanometers to several microns,[1,2] and to manipulate them in all spatial directions.[3,4] This type of force is used to characterize the elastic properties of deformable tiny objects (e.g., living cells5), to obtain quantitative information on mechanical properties at small length scales,[2] and in general, to fix the position of those particles so that they can be manipulated at will. This applies to optically trapped particles, as mentioned above, and to other forms of trapping, like particles deposited on solid substrates, or particles trapped by a tip [e.g., in a scanning tunnel microscope (STM) set up]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
