Liquid-liquid phase transition in simulated liquid Al2O3·2SiO2

Liquid-liquid phase transition in liquid Al2O3·2SiO2 (AS2) has been studied at 4200 K in a model containing 3025 particles under periodic boundary conditions with Born-Mayer type pair potentials via molecular dynamics (MD) simulation. Structure and dynamics of models at densities ranging from 2.60 to 4.20 g cm-3 at a temperature of 4200 K have been analysed in detail through the partial radial distribution functions (PRDF), coordination number distribution, bond-angle distribution, interatomic distances and diffusion constant. We found clear evidence of transition from a tetrahedral to an octahedral network structure in the model upon compression, like that observed in simple oxide systems. Moreover, the transition is accompanied by an anomalous diffusion of components in the system