Structural, Dynamical, and Electrical Properties of Liquid MgSiO3 under Compression: A Molecular Dynamics Study

Abstract

In this paper, the structural and electrical properties in MgSiO3 liquid are investigated by means of molecular dynamics simulation at 3200 K, in the range 0÷30 GPa. The simulation indicates that the structure of MgSiO3 liquid contains MgOy units (y = 3÷9). They have a tendency to forming clusters lead to the structural heterogeneity, which strongly depend on pressure. When pressure increases initial self-diffusion of Si and Mg slightly increase then decrease, while with Oxy atoms, self-diffusion decreases with pressure. In addition, it can be seen that self-diffusion of Mg is significantly larger than self-diffusion of Si and O, while self-diffusion of Si and O is similarly in range pressure 0÷30 GPa. Moreover, the mean electrical coefficient of all atoms strongly decreases under compression. MgSiO3 is a versatile inorganic compound with wide-ranging applications and is considered to be abundant material of Earth’s upper mantle. Therefore, a detailed understanding of silicate melts is essential both for the development of novel materials and for understanding the evolution of our planet.