Nucleation barriers for the liquid-to-crystal transition in simple metals: Experiment vs. simulation

Abstract

Crystal nucleation in the one-component metals Ni and Au is investigated using a combination of differential thermal analysis (DTA) experiments and Monte Carlo (MC) simulations. A novel experimental methodology allows to measure nucleation rates J over a range of 8 orders of magnitude. Evidence is given that these rates correspond to homogeneous nucleation. From the nucleation rates, free energy nucleation barriers ΔG ⋆ are extracted using an ansatz obtained in the framework of classical nucleation theory (CNT). The latter ansatz is rationalized by MC simulations that directly yield estimates for the temperature dependence of ΔG ⋆. The values of ΔG ⋆, as determined from the simulation, are in very good agreement with those extracted from the experiments. The simulations indicate that in the range where experiments are available the corrections to CNT are relatively small, thus justifying the application of CNT. We also discuss how the conditions for heterogeneous nucleation on a flat or structured wall can be obtained from computer simulations.