| AVS 65th International Symposium & Exhibition | |
| Applied Surface Science Division | Tuesday Sessions |
| Session AS-TuA |
| Session: | The Impact of Modeling (Ion, Electron) and Data Analysis on Applied Surface Science, a Celebration of the Career of Barbara Garrison |
| Presenter: | Leonid Zhigilei, University of Virginia |
| Authors: | L. Zhigilei, University of Virginia C.-Y. Shih, University of Virginia M. Shugaev, University of Virginia |
| Correspondent: | Click to Email |
The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this presentation, the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions generated by pulsed laser ablation in liquids [1-4]. The simulations of Ag and Cr targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. One of the interesting predictions of simulations performed at sufficiently high laser fluences, in the regime of phase explosion, is the emergence of Rayleigh–Taylor and Richtmyer–Meshkov hydrodynamic instabilities at the interface between ablation plume and superheated water, leading to the formation of nanojets and emission of large droplets into the water environment. The droplets are rapidly quenched and solidified into nanoparticles featuring complex microstructure and metastable phases, as demonstrated by example structures shown in the middle of the cover. Rapid nucleation and growth of small nanoparticles in the silver–water mixing region and the breakup of the hot metal layer into larger droplets due to the hydrodynamic instabilities represent two distinct mechanisms of the nanoparticle formation that yield nanoparticles of two different size ranges as early as several nanoseconds after the laser irradiation. This computational prediction provides a plausible explanation for experimental observations of bimodal nanoparticle size distributions in short pulse laser ablation experiments.
[1] C.-Y. Shih et al., J. Colloid Interface Sci. 489, 3-17, 2017.
[2] M. V. Shugaev et al., Appl. Surf. Sci. 417, 54-63, 2017.
[3] C.-Y. Shih et al., J. Phys. Chem. C 121, 16549-16567, 2017.
[4] C.-Y. Shih et al., Nanoscale 10, 6900-6910, 2018.