Crystallization and melting in the Lennard-Jones system: Equilibration, relaxation, and long-time dynamics of the moving interface

Nonequilibrium molecular dynamics simulations have been carried out on the growth and melting of the Lennard-Jones (100) interface at small undercoolings and superheatings. Two regimes of linear growth rate were discovered: a short-time regime associated with interface relaxation and a long-time regime associated with the macroscopic limit of growth and melting. It was shown that, if system sizes or equilibration times are taken too small, one will find only the initial regime. On the basis of our very accurate results on the macroscopic growth rates close to equilibrium, the possibility of a discontinuity in the temperature dependence of growth and melting rates at the melting point was ruled out

Simulations of crystallization and melting of the FCC (1 0 0) interface: the crucial role of lattice imperfections

We present nonequilibrium simulations of growth and melting of the atomic FCC (1 0 0) interface. Using Nosé–Hoover dynamics we have carefully studied size effects and approximated the dynamics of the solid–liquid interface in a large system as closely as possible. This led to a clear asymmetry of growth and melting rates close to equilibrium. It was possible to explain these findings in terms of the lattice imperfections in crystalline phases in contact with a liquid phase, which automatically developed during growth simulations but were absent in the melting simulations. It was shown that when melting simulations were started with appropriate starting configurations, the asymmetry could be made to disappear

Crystal growth and interface relaxation rates from fluctuations in an equilibrium simulation of the Lennard-Jones (100) crystal-melt system

The kinetic coefficient of crystallization is calculated according to a previously introduced equilibrium method [Phys. Rev. Lett. 79, 5074 (1997)]. The existence of two regimes of interface relaxation and macroscopic growth, such as they were found in previous nonequilibrium simulations, is fully confirmed by the results of the equilibrium method. Special attention is given to the relation between pressure fluctuations and fluctuations of the amount of crystalline material. Furthermore, we investigate the density and order parameter profiles of the interface and make a clear distinction between the instantaneous structure and the time-averaged profile which is usually presented

Crystal Growth of the Lennard-Jones (100) Surface by Means of Equilibrium and Nonequilibrium Molecular Dynamics

On the basis of Onsager's hypothesis a new method is presented to calculate growth rate constants of various crystal faces from the fluctuations of interfaces during NVT simulations. The method is applied to the (100) face of a Lennard-Jones crystal grown from the melt. The results are in perfect agreement with those obtained by means of NPT nonequilibrium simulations. The new method allows for much better statistics at the cost of much less computation time. The use of Onsager's hypothesis to derive the microscopic expression for the growth rate constant may serve as an example for applications in other fields