Study of the structure of MgSiO₃ system under compression by using ring statistics and voronoi analysis

Abstract

The structural change of MgSiO3 liquid under compression is still one of the most interesting challenges. In this paper, we perform the molecular dynamics simulation to study the structural change of MgSiO3 liquid from 0 to 200 GPa. Ring statistics are analyzed to clarify the intermediate-range order, to explain why the second peak of Si-Si PRDFs splits into 2 subpeaks at 200 GPa, and to show the heterogeneity of MgSiO3. Large rings which form at high pressures would capture the oxygen atoms. Oxygen atoms which have negative charge attract Mg2+ ions, creating magnesium-rich regions. Besides, the Voronoi and Qn distribution changes on the ring with pressure are clarified to give more information about the rings.