Crystal nucleation and growth from supercooled melts

We review our recent work on the crystal nucleation and growth from supercooled model liquids. In particular, we discuss the issue of the selection of a specific crystalline or polymorph during the crystallisation process. We show on a variety of systems how, by modifying the thermodynamic conditions of crystallisation, we achieve the control of polymorphism in model systems. More specifically, by tuning the pressure at which crystallisation takes place in the Lennard-Jones system, we can control the formation of pre-critical, critical or post-critical nuclei of either the thermodynamically stable form or a metastable form. Similarly, we demonstrate how, by tuning the screening parameter in charge-stabilised colloidal suspensions, we achieve the control of polymorphism, either at the pre-critical stage or at the late stage in the crystal growth process. We finally analyse the polymorph selection process during the course of simulations of the crystallisation process using realistic models for atomic fluids (xenon) and spherical molecules (C-60).