Study of the Activation Barrier of Crystallization of a Metastable Liquid Using Metadynamics

Crystallization of a weakly supercooled Lennard-Jones liquid has been investigated by molecular-dynamics simulation using metadynamics. The Steinhardt order parameter Q6 of a group of particles around a randomly chosen atom and the potential energy of the system are chosen as collective variables for metadynamics simulation of the phase transformation. A change in the values of collective variables above the activation crystallization barrier has been traced. The work of formation of a critical nucleus is estimated.