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arXiv · 0704.0990

Dynamics of Size-Selected Gold Nanoparticles Studied by Ultrafast Electron Nanocrystallography

Chong-Yu Ruan·Yoshie Murooka·Ramani K. Raman·Ryan A. Murdick
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Abstract

We report the studies of ultrafast electron nanocrystallography on size-selected Au nanoparticles (2-20 nm) supported on a molecular interface. Reversible surface melting, melting, and recrystallization were investigated with dynamical full-profile radial distribution functions determined with sub-picosecond and picometer accuracies. In an ultrafast photoinduced melting, the nanoparticles are driven to a non-equilibrium transformation, characterized by the initial lattice deformations, nonequilibrium electron-phonon coupling, and upon melting, the collective bonding and debonding, transforming nanocrystals into shelled nanoliquids. The displasive structural excitation at premelting and the coherent transformation with crystal/liquid coexistence during photomelting differ from the reciprocal behavior of recrystallization, where a hot lattice forms from liquid and then thermally contracts. The degree of structural change and the thermodynamics of melting are found to depend on the size of nanoparticle.

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Chong-Yu Ruan, Yoshie Murooka, Ramani K. Raman, Ryan A. Murdick. 2007-04-07. Dynamics of Size-Selected Gold Nanoparticles Studied by Ultrafast Electron Nanocrystallography. https://doi.org/10.1021/nl070269h

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