Frame-by-frame observations of structure fluctuations in single mass-selected Au clusters using aberration-corrected...

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• The potential energy surface (PES) governs nanoparticle structure and dynamics, essential for theoretical simulations.
• Quantitative experimental data on PES parameters for nanosystems are scarce.
• Bulk material parameters may not accurately represent nanoscale behavior.

Purpose of the Study:

• To introduce a novel experimental methodology for characterizing individual nanocluster structures.
• To provide experimental data for validating and improving theoretical models of nanoparticle behavior.
• To enable dynamic measurements of nanoparticles.

Main Methods:

• Utilized aberration-corrected scanning transmission electron microscopy (ac-STEM) in high-angle annular dark-field (HAADF) mode.
• Analyzed individual gold nanoclusters (309 ± 15 atoms) deposited on an amorphous carbon film.
• Obtained frame-by-frame structural information of single nanoclusters.

Main Results:

• Identified major isomers including icosahedral (Ih), decahedral (Dh), and face-centered-cubic (fcc).
• Observed numerous amorphous (glassy) structures alongside crystalline isomers.
• Results align with ensemble measurements, validating the single-particle approach.

Conclusions:

• The developed ac-STEM methodology enables frame-by-frame analysis of single nanocluster structures.
• This technique facilitates the quantitative experimental measurement of critical PES parameters.
• Paves the way for dynamic studies of diverse nanoparticles.