Dynamics of liquid nanodroplet formation in nanosecond laser ablation of metals

The laser ablation mechanisms of metallic targets leading to liquid nanodroplet ejection are of wide interest both from a fundamental point of view and for applications in various fields, especially when nanoparticle synthesis is required. The phase explosion process was recognized as the driving mechanism of the expulsion of a mixture of vapor and liquid nanodroplets in the short pulse laser ablation of metals. A model based on thermodynamics that links the theory of homogeneous vapor bubble nucleation to the size distribution of the generated liquid nanoclusters has been recently proposed. The present work aims to take a step ahead to remove some assumptions made in previous work. Here an improved computational approach allows us to describe time-dependent nucleation in a homogeneous system with no temperature spatial gradients under nanosecond laser irradiation. Numerical results regarding the size distribution of formed liquid clusters and the time evolution of the process are shown for aluminum, iron, cobalt, nickel, copper, silver and gold. Connections with experimental data and molecular dynamics simulations, when available from literature, are reported and discussed. (C) 2016 Elsevier B.V. All rights reserved.