  Metallic nanoparticles, liquefied by fast laser irradiation, go through a
rapid change of shape attempting to minimize their surface energy. The
resulting nanodrops may be ejected from the substrate when the mechanisms
leading to dewetting are sufficiently strong, as in the experiments involving
gold nanoparticles [Habenicht et al., Science 309, 2043 (2005)]. We use a
direct continuum-level approach to accurately model the process of liquid
nanodrop formation and the subsequent ejection from the substrate. Our
computations show a significant role of inertial effects and an elaborate
interplay of initial geometry and wetting properties: e.g., we can control the
direction of ejection by prescribing appropriate initial shape and/or wetting
properties. The basic insight regarding ejection itself can be reached by
considering a simple effective model based on an energy balance. We validate
our computations by comparing directly with the experiments specified above
involving the length scales measured in hundreds of nanometers, and with
molecular dynamics simulations on much shorter scales measured in tens of
atomic diameters, as in [M. Fuentes-Cabrera et al., Phys. Rev. E 83, 041603
(2011)]. The quantitative agreement, in addition to illustrating how to
controlling particle ejection, shows utility of continuum-based simulation in
describing dynamics on nanoscale quantitatively, even in a complex setting as
considered here.
