Non-equilibrium molecular dynamics and continuum modelling of transient freezing of atomistic solids

In this work we investigate the transient solidification of a Lennard-Jones liquid using non-equilibrium molecular dynamics simulations and continuum heat transfer theory. The are performed in slab-shaped boxes, where cold thermostat placed at centre box drives liquid. Two well-defined solid fronts propagate outwards from towards ends until is completed. A phase change model that accounts for difference between densities formulated to describe evolution temperature position front. Simulation results small large nanoscale system, sizes 30.27 nm 60.54 nm, compared with predictions theoretical model. Following period ~ 20-40 ps displacement front 1-2.5 find theory show good agreement. We use fact combine simulation approaches design simple procedure calculate latent associated liquid-solid transition. also perform homogeneous freezing process, i.e. absence gradient constant temperature, by quenching supercooled temperatures. demonstrate that, comparable conditions, rate homogenous much faster than one obtained under thermal gradient. Our study conclusions should be general interest wide range atomistic solids.